* Lazy Versioning Check, Conditional SSE Entry Fetch, HEAD Request Optimization * revert Reverted the conditional versioning check to always check versioning status Reverted the conditional SSE entry fetch to always fetch entry metadata Reverted the conditional versioning check to always check versioning status Reverted the conditional SSE entry fetch to always fetch entry metadata * Lazy Entry Fetch for SSE, Skip Conditional Header Check * SSE-KMS headers are present, this is not an SSE-C request (mutually exclusive) * SSE-C is mutually exclusive with SSE-S3 and SSE-KMS * refactor * Removed Premature Mutual Exclusivity Check * check for the presence of the X-Amz-Server-Side-Encryption header * not used * fmt * directly read write volume servers * HTTP Range Request Support * set header * md5 * copy object * fix sse * fmt * implement sse * sse continue * fixed the suffix range bug (bytes=-N for "last N bytes") * debug logs * Missing PartsCount Header * profiling * url encoding * test_multipart_get_part * headers * debug * adjust log level * handle part number * Update s3api_object_handlers.go * nil safety * set ModifiedTsNs * remove * nil check * fix sse header * same logic as filer * decode values * decode ivBase64 * s3: Fix SSE decryption JWT authentication and streaming errors Critical fix for SSE (Server-Side Encryption) test failures: 1. **JWT Authentication Bug** (Root Cause): - Changed from GenJwtForFilerServer to GenJwtForVolumeServer - S3 API now uses correct JWT when directly reading from volume servers - Matches filer's authentication pattern for direct volume access - Fixes 'unexpected EOF' and 500 errors in SSE tests 2. **Streaming Error Handling**: - Added error propagation in getEncryptedStreamFromVolumes goroutine - Use CloseWithError() to properly communicate stream failures - Added debug logging for streaming errors 3. **Response Header Timing**: - Removed premature WriteHeader(http.StatusOK) call - Let Go's http package write status automatically on first write - Prevents header lock when errors occur during streaming 4. **Enhanced SSE Decryption Debugging**: - Added IV/Key validation and logging for SSE-C, SSE-KMS, SSE-S3 - Better error messages for missing or invalid encryption metadata - Added glog.V(2) debugging for decryption setup This fixes SSE integration test failures where encrypted objects could not be retrieved due to volume server authentication failures. The JWT bug was causing volume servers to reject requests, resulting in truncated/empty streams (EOF) or internal errors. * s3: Fix SSE multipart upload metadata preservation Critical fix for SSE multipart upload test failures (SSE-C and SSE-KMS): **Root Cause - Incomplete SSE Metadata Copying**: The old code only tried to copy 'SeaweedFSSSEKMSKey' from the first part to the completed object. This had TWO bugs: 1. **Wrong Constant Name** (Key Mismatch Bug): - Storage uses: SeaweedFSSSEKMSKeyHeader = 'X-SeaweedFS-SSE-KMS-Key' - Old code read: SeaweedFSSSEKMSKey = 'x-seaweedfs-sse-kms-key' - Result: SSE-KMS metadata was NEVER copied → 500 errors 2. **Missing SSE-C and SSE-S3 Headers**: - SSE-C requires: IV, Algorithm, KeyMD5 - SSE-S3 requires: encrypted key data + standard headers - Old code: copied nothing for SSE-C/SSE-S3 → decryption failures **Fix - Complete SSE Header Preservation**: Now copies ALL SSE headers from first part to completed object: - SSE-C: SeaweedFSSSEIV, CustomerAlgorithm, CustomerKeyMD5 - SSE-KMS: SeaweedFSSSEKMSKeyHeader, AwsKmsKeyId, ServerSideEncryption - SSE-S3: SeaweedFSSSES3Key, ServerSideEncryption Applied consistently to all 3 code paths: 1. Versioned buckets (creates version file) 2. Suspended versioning (creates main object with null versionId) 3. Non-versioned buckets (creates main object) **Why This Is Correct**: The headers copied EXACTLY match what putToFiler stores during part upload (lines 496-521 in s3api_object_handlers_put.go). This ensures detectPrimarySSEType() can correctly identify encrypted multipart objects and trigger inline decryption with proper metadata. Fixes: TestSSEMultipartUploadIntegration (SSE-C and SSE-KMS subtests) * s3: Add debug logging for versioning state diagnosis Temporary debug logging to diagnose test_versioning_obj_plain_null_version_overwrite_suspended failure. Added glog.V(0) logging to show: 1. setBucketVersioningStatus: when versioning status is changed 2. PutObjectHandler: what versioning state is detected (Enabled/Suspended/none) 3. PutObjectHandler: which code path is taken (putVersionedObject vs putSuspendedVersioningObject) This will help identify if: - The versioning status is being set correctly in bucket config - The cache is returning stale/incorrect versioning state - The switch statement is correctly routing to suspended vs enabled handlers * s3: Enhanced versioning state tracing for suspended versioning diagnosis Added comprehensive logging across the entire versioning state flow: PutBucketVersioningHandler: - Log requested status (Enabled/Suspended) - Log when calling setBucketVersioningStatus - Log success/failure of status change setBucketVersioningStatus: - Log bucket and status being set - Log when config is updated - Log completion with error code updateBucketConfig: - Log versioning state being written to cache - Immediate cache verification after Set - Log if cache verification fails getVersioningState: - Log bucket name and state being returned - Log if object lock forces VersioningEnabled - Log errors This will reveal: 1. If PutBucketVersioning(Suspended) is reaching the handler 2. If the cache update succeeds 3. What state getVersioningState returns during PUT 4. Any cache consistency issues Expected to show why bucket still reports 'Enabled' after 'Suspended' call. * s3: Add SSE chunk detection debugging for multipart uploads Added comprehensive logging to diagnose why TestSSEMultipartUploadIntegration fails: detectPrimarySSEType now logs: 1. Total chunk count and extended header count 2. All extended headers with 'sse'/'SSE'/'encryption' in the name 3. For each chunk: index, SseType, and whether it has metadata 4. Final SSE type counts (SSE-C, SSE-KMS, SSE-S3) This will reveal if: - Chunks are missing SSE metadata after multipart completion - Extended headers are copied correctly from first part - The SSE detection logic is working correctly Expected to show if chunks have SseType=0 (none) or proper SSE types set. * s3: Trace SSE chunk metadata through multipart completion and retrieval Added end-to-end logging to track SSE chunk metadata lifecycle: **During Multipart Completion (filer_multipart.go)**: 1. Log finalParts chunks BEFORE mkFile - shows SseType and metadata 2. Log versionEntry.Chunks INSIDE mkFile callback - shows if mkFile preserves SSE info 3. Log success after mkFile completes **During GET Retrieval (s3api_object_handlers.go)**: 1. Log retrieved entry chunks - shows SseType and metadata after retrieval 2. Log detected SSE type result This will reveal at which point SSE chunk metadata is lost: - If finalParts have SSE metadata but versionEntry.Chunks don't → mkFile bug - If versionEntry.Chunks have SSE metadata but retrieved chunks don't → storage/retrieval bug - If chunks never have SSE metadata → multipart completion SSE processing bug Expected to show chunks with SseType=NONE during retrieval even though they were created with proper SseType during multipart completion. * s3: Fix SSE-C multipart IV base64 decoding bug **Critical Bug Found**: SSE-C multipart uploads were failing because: Root Cause: - entry.Extended[SeaweedFSSSEIV] stores base64-encoded IV (24 bytes for 16-byte IV) - SerializeSSECMetadata expects raw IV bytes (16 bytes) - During multipart completion, we were passing base64 IV directly → serialization error Error Message: "Failed to serialize SSE-C metadata for chunk in part X: invalid IV length: expected 16 bytes, got 24" Fix: - Base64-decode IV before passing to SerializeSSECMetadata - Added error handling for decode failures Impact: - SSE-C multipart uploads will now correctly serialize chunk metadata - Chunks will have proper SSE metadata for decryption during GET This fixes the SSE-C subtest of TestSSEMultipartUploadIntegration. SSE-KMS still has a separate issue (error code 23) being investigated. * fixes * kms sse * handle retry if not found in .versions folder and should read the normal object * quick check (no retries) to see if the .versions/ directory exists * skip retry if object is not found * explicit update to avoid sync delay * fix map update lock * Remove fmt.Printf debug statements * Fix SSE-KMS multipart base IV fallback to fail instead of regenerating * fmt * Fix ACL grants storage logic * header handling * nil handling * range read for sse content * test range requests for sse objects * fmt * unused code * upload in chunks * header case * fix url * bucket policy error vs bucket not found * jwt handling * fmt * jwt in request header * Optimize Case-Insensitive Prefix Check * dead code * Eliminated Unnecessary Stream Prefetch for Multipart SSE * range sse * sse * refactor * context * fmt * fix type * fix SSE-C IV Mismatch * Fix Headers Being Set After WriteHeader * fix url parsing * propergate sse headers * multipart sse-s3 * aws sig v4 authen * sse kms * set content range * better errors * Update s3api_object_handlers_copy.go * Update s3api_object_handlers.go * Update s3api_object_handlers.go * avoid magic number * clean up * Update s3api_bucket_policy_handlers.go * fix url parsing * context * data and metadata both use background context * adjust the offset * SSE Range Request IV Calculation * adjust logs * IV relative to offset in each part, not the whole file * collect logs * offset * fix offset * fix url * logs * variable * jwt * Multipart ETag semantics: conditionally set object-level Md5 for single-chunk uploads only. * sse * adjust IV and offset * multipart boundaries * ensures PUT and GET operations return consistent ETags * Metadata Header Case * CommonPrefixes Sorting with URL Encoding * always sort * remove the extra PathUnescape call * fix the multipart get part ETag * the FileChunk is created without setting ModifiedTsNs * Sort CommonPrefixes lexicographically to match AWS S3 behavior * set md5 for multipart uploads * prevents any potential data loss or corruption in the small-file inline storage path * compiles correctly * decryptedReader will now be properly closed after use * Fixed URL encoding and sort order for CommonPrefixes * Update s3api_object_handlers_list.go * SSE-x Chunk View Decryption * Different IV offset calculations for single-part vs multipart objects * still too verbose in logs * less logs * ensure correct conversion * fix listing * nil check * minor fixes * nil check * single character delimiter * optimize * range on empty object or zero-length * correct IV based on its position within that part, not its position in the entire object * adjust offset * offset Fetch FULL encrypted chunk (not just the range) Adjust IV by PartOffset/ChunkOffset only Decrypt full chunk Skip in the DECRYPTED stream to reach OffsetInChunk * look breaking * refactor * error on no content * handle intra-block byte skipping * Incomplete HTTP Response Error Handling * multipart SSE * Update s3api_object_handlers.go * address comments * less logs * handling directory * Optimized rejectDirectoryObjectWithoutSlash() to avoid unnecessary lookups * Revert "handling directory" This reverts commit 3a335f0ac33c63f51975abc63c40e5328857a74b. * constant * Consolidate nil entry checks in GetObjectHandler * add range tests * Consolidate redundant nil entry checks in HeadObjectHandler * adjust logs * SSE type * large files * large files Reverted the plain-object range test * ErrNoEncryptionConfig * Fixed SSERangeReader Infinite Loop Vulnerability * Fixed SSE-KMS Multipart ChunkReader HTTP Body Leak * handle empty directory in S3, added PyArrow tests * purge unused code * Update s3_parquet_test.py * Update requirements.txt * According to S3 specifications, when both partNumber and Range are present, the Range should apply within the selected part's boundaries, not to the full object. * handle errors * errors after writing header * https * fix: Wait for volume assignment readiness before running Parquet tests The test-implicit-dir-with-server test was failing with an Internal Error because volume assignment was not ready when tests started. This fix adds a check that attempts a volume assignment and waits for it to succeed before proceeding with tests. This ensures that: 1. Volume servers are registered with the master 2. Volume growth is triggered if needed 3. The system can successfully assign volumes for writes Fixes the timeout issue where boto3 would retry 4 times and fail with 'We encountered an internal error, please try again.' * sse tests * store derived IV * fix: Clean up gRPC ports between tests to prevent port conflicts The second test (test-implicit-dir-with-server) was failing because the volume server's gRPC port (18080 = VOLUME_PORT + 10000) was still in use from the first test. The cleanup code only killed HTTP port processes, not gRPC port processes. Added cleanup for gRPC ports in all stop targets: - Master gRPC: MASTER_PORT + 10000 (19333) - Volume gRPC: VOLUME_PORT + 10000 (18080) - Filer gRPC: FILER_PORT + 10000 (18888) This ensures clean state between test runs in CI. * add import * address comments * docs: Add placeholder documentation files for Parquet test suite Added three missing documentation files referenced in test/s3/parquet/README.md: 1. TEST_COVERAGE.md - Documents 43 total test cases (17 Go unit tests, 6 Python integration tests, 20 Python end-to-end tests) 2. FINAL_ROOT_CAUSE_ANALYSIS.md - Explains the s3fs compatibility issue with PyArrow, the implicit directory problem, and how the fix works 3. MINIO_DIRECTORY_HANDLING.md - Compares MinIO's directory handling approach with SeaweedFS's implementation Each file contains: - Title and overview - Key technical details relevant to the topic - TODO sections for future expansion These placeholder files resolve the broken README links and provide structure for future detailed documentation. * clean up if metadata operation failed * Update s3_parquet_test.py * clean up * Update Makefile * Update s3_parquet_test.py * Update Makefile * Handle ivSkip for non-block-aligned offsets * Update README.md * stop volume server faster * stop volume server in 1 second * different IV for each chunk in SSE-S3 and SSE-KMS * clean up if fails * testing upload * error propagation * fmt * simplify * fix copying * less logs * endian * Added marshaling error handling * handling invalid ranges * error handling for adding to log buffer * fix logging * avoid returning too quickly and ensure proper cleaning up * Activity Tracking for Disk Reads * Cleanup Unused Parameters * Activity Tracking for Kafka Publishers * Proper Test Error Reporting * refactoring * less logs * less logs * go fmt * guard it with if entry.Attributes.TtlSec > 0 to match the pattern used elsewhere. * Handle bucket-default encryption config errors explicitly for multipart * consistent activity tracking * obsolete code for s3 on filer read/write handlers * Update weed/s3api/s3api_object_handlers_list.go Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com> --------- Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
-apply (instead of -force). (#7450)
SeaweedFS
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- SeaweedFS Mailing List
- Wiki Documentation
- SeaweedFS White Paper
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- SeaweedFS Introduction Slides 2021.5
- SeaweedFS Introduction Slides 2019.3
Table of Contents
- Quick Start
- Introduction
- Features
- Example: Using Seaweed Object Store
- Architecture
- Compared to Other File Systems
- Dev Plan
- Installation Guide
- Disk Related Topics
- Benchmark
- Enterprise
- License
Quick Start
Quick Start for S3 API on Docker
docker run -p 8333:8333 chrislusf/seaweedfs server -s3
Quick Start with Single Binary
- Download the latest binary from https://github.com/seaweedfs/seaweedfs/releases and unzip a single binary file
weedorweed.exe. Or rungo install github.com/seaweedfs/seaweedfs/weed@latest. export AWS_ACCESS_KEY_ID=admin ; export AWS_SECRET_ACCESS_KEY=keyas the admin credentials to access the object store.- Run
weed server -dir=/some/data/dir -s3to start one master, one volume server, one filer, and one S3 gateway.
Also, to increase capacity, just add more volume servers by running weed volume -dir="/some/data/dir2" -mserver="<master_host>:9333" -port=8081 locally, or on a different machine, or on thousands of machines. That is it!
Quick Start SeaweedFS S3 on AWS
- Setup fast production-ready SeaweedFS S3 on AWS with cloudformation
Introduction
SeaweedFS is a simple and highly scalable distributed file system. There are two objectives:
- to store billions of files!
- to serve the files fast!
SeaweedFS started as an Object Store to handle small files efficiently. Instead of managing all file metadata in a central master, the central master only manages volumes on volume servers, and these volume servers manage files and their metadata. This relieves concurrency pressure from the central master and spreads file metadata into volume servers, allowing faster file access (O(1), usually just one disk read operation).
There is only 40 bytes of disk storage overhead for each file's metadata. It is so simple with O(1) disk reads that you are welcome to challenge the performance with your actual use cases.
SeaweedFS started by implementing Facebook's Haystack design paper. Also, SeaweedFS implements erasure coding with ideas from f4: Facebook’s Warm BLOB Storage System, and has a lot of similarities with Facebook’s Tectonic Filesystem
On top of the object store, optional Filer can support directories and POSIX attributes. Filer is a separate linearly-scalable stateless server with customizable metadata stores, e.g., MySql, Postgres, Redis, Cassandra, HBase, Mongodb, Elastic Search, LevelDB, RocksDB, Sqlite, MemSql, TiDB, Etcd, CockroachDB, YDB, etc.
For any distributed key value stores, the large values can be offloaded to SeaweedFS. With the fast access speed and linearly scalable capacity, SeaweedFS can work as a distributed Key-Large-Value store.
SeaweedFS can transparently integrate with the cloud. With hot data on local cluster, and warm data on the cloud with O(1) access time, SeaweedFS can achieve both fast local access time and elastic cloud storage capacity. What's more, the cloud storage access API cost is minimized. Faster and cheaper than direct cloud storage!
Features
Additional Features
- Can choose no replication or different replication levels, rack and data center aware.
- Automatic master servers failover - no single point of failure (SPOF).
- Automatic Gzip compression depending on file MIME type.
- Automatic compaction to reclaim disk space after deletion or update.
- Automatic entry TTL expiration.
- Any server with some disk space can add to the total storage space.
- Adding/Removing servers does not cause any data re-balancing unless triggered by admin commands.
- Optional picture resizing.
- Support ETag, Accept-Range, Last-Modified, etc.
- Support in-memory/leveldb/readonly mode tuning for memory/performance balance.
- Support rebalancing the writable and readonly volumes.
- Customizable Multiple Storage Tiers: Customizable storage disk types to balance performance and cost.
- Transparent cloud integration: unlimited capacity via tiered cloud storage for warm data.
- Erasure Coding for warm storage Rack-Aware 10.4 erasure coding reduces storage cost and increases availability.
Filer Features
- Filer server provides "normal" directories and files via HTTP.
- File TTL automatically expires file metadata and actual file data.
- Mount filer reads and writes files directly as a local directory via FUSE.
- Filer Store Replication enables HA for filer meta data stores.
- Active-Active Replication enables asynchronous one-way or two-way cross cluster continuous replication.
- Amazon S3 compatible API accesses files with S3 tooling.
- Hadoop Compatible File System accesses files from Hadoop/Spark/Flink/etc or even runs HBase.
- Async Replication To Cloud has extremely fast local access and backups to Amazon S3, Google Cloud Storage, Azure, BackBlaze.
- WebDAV accesses as a mapped drive on Mac and Windows, or from mobile devices.
- AES256-GCM Encrypted Storage safely stores the encrypted data.
- Super Large Files stores large or super large files in tens of TB.
- Cloud Drive mounts cloud storage to local cluster, cached for fast read and write with asynchronous write back.
- Gateway to Remote Object Store mirrors bucket operations to remote object storage, in addition to Cloud Drive
Kubernetes
- Kubernetes CSI Driver A Container Storage Interface (CSI) Driver.
- SeaweedFS Operator
Example: Using Seaweed Object Store
By default, the master node runs on port 9333, and the volume nodes run on port 8080. Let's start one master node, and two volume nodes on port 8080 and 8081. Ideally, they should be started from different machines. We'll use localhost as an example.
SeaweedFS uses HTTP REST operations to read, write, and delete. The responses are in JSON or JSONP format.
Start Master Server
> ./weed master
Start Volume Servers
> weed volume -dir="/tmp/data1" -max=5 -mserver="localhost:9333" -port=8080 &
> weed volume -dir="/tmp/data2" -max=10 -mserver="localhost:9333" -port=8081 &
Write File
To upload a file: first, send a HTTP POST, PUT, or GET request to /dir/assign to get an fid and a volume server URL:
> curl http://localhost:9333/dir/assign
{"count":1,"fid":"3,01637037d6","url":"127.0.0.1:8080","publicUrl":"localhost:8080"}
Second, to store the file content, send a HTTP multi-part POST request to url + '/' + fid from the response:
> curl -F file=@/home/chris/myphoto.jpg http://127.0.0.1:8080/3,01637037d6
{"name":"myphoto.jpg","size":43234,"eTag":"1cc0118e"}
To update, send another POST request with updated file content.
For deletion, send an HTTP DELETE request to the same url + '/' + fid URL:
> curl -X DELETE http://127.0.0.1:8080/3,01637037d6
Save File Id
Now, you can save the fid, 3,01637037d6 in this case, to a database field.
The number 3 at the start represents a volume id. After the comma, it's one file key, 01, and a file cookie, 637037d6.
The volume id is an unsigned 32-bit integer. The file key is an unsigned 64-bit integer. The file cookie is an unsigned 32-bit integer, used to prevent URL guessing.
The file key and file cookie are both coded in hex. You can store the <volume id, file key, file cookie> tuple in your own format, or simply store the fid as a string.
If stored as a string, in theory, you would need 8+1+16+8=33 bytes. A char(33) would be enough, if not more than enough, since most uses will not need 2^32 volumes.
If space is really a concern, you can store the file id in your own format. You would need one 4-byte integer for volume id, 8-byte long number for file key, and a 4-byte integer for the file cookie. So 16 bytes are more than enough.
Read File
Here is an example of how to render the URL.
First look up the volume server's URLs by the file's volumeId:
> curl http://localhost:9333/dir/lookup?volumeId=3
{"volumeId":"3","locations":[{"publicUrl":"localhost:8080","url":"localhost:8080"}]}
Since (usually) there are not too many volume servers, and volumes don't move often, you can cache the results most of the time. Depending on the replication type, one volume can have multiple replica locations. Just randomly pick one location to read.
Now you can take the public URL, render the URL or directly read from the volume server via URL:
http://localhost:8080/3,01637037d6.jpg
Notice we add a file extension ".jpg" here. It's optional and just one way for the client to specify the file content type.
If you want a nicer URL, you can use one of these alternative URL formats:
http://localhost:8080/3/01637037d6/my_preferred_name.jpg
http://localhost:8080/3/01637037d6.jpg
http://localhost:8080/3,01637037d6.jpg
http://localhost:8080/3/01637037d6
http://localhost:8080/3,01637037d6
If you want to get a scaled version of an image, you can add some params:
http://localhost:8080/3/01637037d6.jpg?height=200&width=200
http://localhost:8080/3/01637037d6.jpg?height=200&width=200&mode=fit
http://localhost:8080/3/01637037d6.jpg?height=200&width=200&mode=fill
Rack-Aware and Data Center-Aware Replication
SeaweedFS applies the replication strategy at a volume level. So, when you are getting a file id, you can specify the replication strategy. For example:
curl http://localhost:9333/dir/assign?replication=001
The replication parameter options are:
000: no replication
001: replicate once on the same rack
010: replicate once on a different rack, but same data center
100: replicate once on a different data center
200: replicate twice on two different data center
110: replicate once on a different rack, and once on a different data center
More details about replication can be found on the wiki.
You can also set the default replication strategy when starting the master server.
Allocate File Key on Specific Data Center
Volume servers can be started with a specific data center name:
weed volume -dir=/tmp/1 -port=8080 -dataCenter=dc1
weed volume -dir=/tmp/2 -port=8081 -dataCenter=dc2
When requesting a file key, an optional "dataCenter" parameter can limit the assigned volume to the specific data center. For example, this specifies that the assigned volume should be limited to 'dc1':
http://localhost:9333/dir/assign?dataCenter=dc1
Other Features
- No Single Point of Failure
- Insert with your own keys
- Chunking large files
- Collection as a Simple Name Space
Object Store Architecture
Usually distributed file systems split each file into chunks, a central master keeps a mapping of filenames, chunk indices to chunk handles, and also which chunks each chunk server has.
The main drawback is that the central master can't handle many small files efficiently, and since all read requests need to go through the chunk master, so it might not scale well for many concurrent users.
Instead of managing chunks, SeaweedFS manages data volumes in the master server. Each data volume is 32GB in size, and can hold a lot of files. And each storage node can have many data volumes. So the master node only needs to store the metadata about the volumes, which is a fairly small amount of data and is generally stable.
The actual file metadata is stored in each volume on volume servers. Since each volume server only manages metadata of files on its own disk, with only 16 bytes for each file, all file access can read file metadata just from memory and only needs one disk operation to actually read file data.
For comparison, consider that an xfs inode structure in Linux is 536 bytes.
Master Server and Volume Server
The architecture is fairly simple. The actual data is stored in volumes on storage nodes. One volume server can have multiple volumes, and can both support read and write access with basic authentication.
All volumes are managed by a master server. The master server contains the volume id to volume server mapping. This is fairly static information, and can be easily cached.
On each write request, the master server also generates a file key, which is a growing 64-bit unsigned integer. Since write requests are not generally as frequent as read requests, one master server should be able to handle the concurrency well.
Write and Read files
When a client sends a write request, the master server returns (volume id, file key, file cookie, volume node URL) for the file. The client then contacts the volume node and POSTs the file content.
When a client needs to read a file based on (volume id, file key, file cookie), it asks the master server by the volume id for the (volume node URL, volume node public URL), or retrieves this from a cache. Then the client can GET the content, or just render the URL on web pages and let browsers fetch the content.
Please see the example for details on the write-read process.
Storage Size
In the current implementation, each volume can hold 32 gibibytes (32GiB or 8x2^32 bytes). This is because we align content to 8 bytes. We can easily increase this to 64GiB, or 128GiB, or more, by changing 2 lines of code, at the cost of some wasted padding space due to alignment.
There can be 4 gibibytes (4GiB or 2^32 bytes) of volumes. So the total system size is 8 x 4GiB x 4GiB which is 128 exbibytes (128EiB or 2^67 bytes).
Each individual file size is limited to the volume size.
Saving memory
All file meta information stored on a volume server is readable from memory without disk access. Each file takes just a 16-byte map entry of <64bit key, 32bit offset, 32bit size>. Of course, each map entry has its own space cost for the map. But usually the disk space runs out before the memory does.
Tiered Storage to the cloud
The local volume servers are much faster, while cloud storages have elastic capacity and are actually more cost-efficient if not accessed often (usually free to upload, but relatively costly to access). With the append-only structure and O(1) access time, SeaweedFS can take advantage of both local and cloud storage by offloading the warm data to the cloud.
Usually hot data are fresh and warm data are old. SeaweedFS puts the newly created volumes on local servers, and optionally upload the older volumes on the cloud. If the older data are accessed less often, this literally gives you unlimited capacity with limited local servers, and still fast for new data.
With the O(1) access time, the network latency cost is kept at minimum.
If the hot/warm data is split as 20/80, with 20 servers, you can achieve storage capacity of 100 servers. That's a cost saving of 80%! Or you can repurpose the 80 servers to store new data also, and get 5X storage throughput.
Compared to Other File Systems
Most other distributed file systems seem more complicated than necessary.
SeaweedFS is meant to be fast and simple, in both setup and operation. If you do not understand how it works when you reach here, we've failed! Please raise an issue with any questions or update this file with clarifications.
SeaweedFS is constantly moving forward. Same with other systems. These comparisons can be outdated quickly. Please help to keep them updated.
Compared to HDFS
HDFS uses the chunk approach for each file, and is ideal for storing large files.
SeaweedFS is ideal for serving relatively smaller files quickly and concurrently.
SeaweedFS can also store extra large files by splitting them into manageable data chunks, and store the file ids of the data chunks into a meta chunk. This is managed by "weed upload/download" tool, and the weed master or volume servers are agnostic about it.
Compared to GlusterFS, Ceph
The architectures are mostly the same. SeaweedFS aims to store and read files fast, with a simple and flat architecture. The main differences are
- SeaweedFS optimizes for small files, ensuring O(1) disk seek operation, and can also handle large files.
- SeaweedFS statically assigns a volume id for a file. Locating file content becomes just a lookup of the volume id, which can be easily cached.
- SeaweedFS Filer metadata store can be any well-known and proven data store, e.g., Redis, Cassandra, HBase, Mongodb, Elastic Search, MySql, Postgres, Sqlite, MemSql, TiDB, CockroachDB, Etcd, YDB etc, and is easy to customize.
- SeaweedFS Volume server also communicates directly with clients via HTTP, supporting range queries, direct uploads, etc.
| System | File Metadata | File Content Read | POSIX | REST API | Optimized for large number of small files |
|---|---|---|---|---|---|
| SeaweedFS | lookup volume id, cacheable | O(1) disk seek | Yes | Yes | |
| SeaweedFS Filer | Linearly Scalable, Customizable | O(1) disk seek | FUSE | Yes | Yes |
| GlusterFS | hashing | FUSE, NFS | |||
| Ceph | hashing + rules | FUSE | Yes | ||
| MooseFS | in memory | FUSE | No | ||
| MinIO | separate meta file for each file | Yes | No |
Compared to GlusterFS
GlusterFS stores files, both directories and content, in configurable volumes called "bricks".
GlusterFS hashes the path and filename into ids, and assigned to virtual volumes, and then mapped to "bricks".
Compared to MooseFS
MooseFS chooses to neglect small file issue. From moosefs 3.0 manual, "even a small file will occupy 64KiB plus additionally 4KiB of checksums and 1KiB for the header", because it "was initially designed for keeping large amounts (like several thousands) of very big files"
MooseFS Master Server keeps all meta data in memory. Same issue as HDFS namenode.
Compared to Ceph
Ceph can be setup similar to SeaweedFS as a key->blob store. It is much more complicated, with the need to support layers on top of it. Here is a more detailed comparison
SeaweedFS has a centralized master group to look up free volumes, while Ceph uses hashing and metadata servers to locate its objects. Having a centralized master makes it easy to code and manage.
Ceph, like SeaweedFS, is based on the object store RADOS. Ceph is rather complicated with mixed reviews.
Ceph uses CRUSH hashing to automatically manage data placement, which is efficient to locate the data. But the data has to be placed according to the CRUSH algorithm. Any wrong configuration would cause data loss. Topology changes, such as adding new servers to increase capacity, will cause data migration with high IO cost to fit the CRUSH algorithm. SeaweedFS places data by assigning them to any writable volumes. If writes to one volume failed, just pick another volume to write. Adding more volumes is also as simple as it can be.
SeaweedFS is optimized for small files. Small files are stored as one continuous block of content, with at most 8 unused bytes between files. Small file access is O(1) disk read.
SeaweedFS Filer uses off-the-shelf stores, such as MySql, Postgres, Sqlite, Mongodb, Redis, Elastic Search, Cassandra, HBase, MemSql, TiDB, CockroachCB, Etcd, YDB, to manage file directories. These stores are proven, scalable, and easier to manage.
| SeaweedFS | comparable to Ceph | advantage |
|---|---|---|
| Master | MDS | simpler |
| Volume | OSD | optimized for small files |
| Filer | Ceph FS | linearly scalable, Customizable, O(1) or O(logN) |
Compared to MinIO
MinIO follows AWS S3 closely and is ideal for testing for S3 API. It has good UI, policies, versionings, etc. SeaweedFS is trying to catch up here. It is also possible to put MinIO as a gateway in front of SeaweedFS later.
MinIO metadata are in simple files. Each file write will incur extra writes to corresponding meta file.
MinIO does not have optimization for lots of small files. The files are simply stored as is to local disks. Plus the extra meta file and shards for erasure coding, it only amplifies the LOSF problem.
MinIO has multiple disk IO to read one file. SeaweedFS has O(1) disk reads, even for erasure coded files.
MinIO has full-time erasure coding. SeaweedFS uses replication on hot data for faster speed and optionally applies erasure coding on warm data.
MinIO does not have POSIX-like API support.
MinIO has specific requirements on storage layout. It is not flexible to adjust capacity. In SeaweedFS, just start one volume server pointing to the master. That's all.
Dev Plan
- More tools and documentation, on how to manage and scale the system.
- Read and write stream data.
- Support structured data.
This is a super exciting project! And we need helpers and support!
Installation Guide
Installation guide for users who are not familiar with golang
Step 1: install go on your machine and setup the environment by following the instructions at:
https://golang.org/doc/install
make sure to define your $GOPATH
Step 2: checkout this repo:
git clone https://github.com/seaweedfs/seaweedfs.git
Step 3: download, compile, and install the project by executing the following command
cd seaweedfs/weed && make install
Once this is done, you will find the executable "weed" in your $GOPATH/bin directory
Disk Related Topics
Hard Drive Performance
When testing read performance on SeaweedFS, it basically becomes a performance test of your hard drive's random read speed. Hard drives usually get 100MB/s~200MB/s.
Solid State Disk
To modify or delete small files, SSD must delete a whole block at a time, and move content in existing blocks to a new block. SSD is fast when brand new, but will get fragmented over time and you have to garbage collect, compacting blocks. SeaweedFS is friendly to SSD since it is append-only. Deletion and compaction are done on volume level in the background, not slowing reading and not causing fragmentation.
Benchmark
My Own Unscientific Single Machine Results on Mac Book with Solid State Disk, CPU: 1 Intel Core i7 2.6GHz.
Write 1 million 1KB file:
Concurrency Level: 16
Time taken for tests: 66.753 seconds
Completed requests: 1048576
Failed requests: 0
Total transferred: 1106789009 bytes
Requests per second: 15708.23 [#/sec]
Transfer rate: 16191.69 [Kbytes/sec]
Connection Times (ms)
min avg max std
Total: 0.3 1.0 84.3 0.9
Percentage of the requests served within a certain time (ms)
50% 0.8 ms
66% 1.0 ms
75% 1.1 ms
80% 1.2 ms
90% 1.4 ms
95% 1.7 ms
98% 2.1 ms
99% 2.6 ms
100% 84.3 ms
Randomly read 1 million files:
Concurrency Level: 16
Time taken for tests: 22.301 seconds
Completed requests: 1048576
Failed requests: 0
Total transferred: 1106812873 bytes
Requests per second: 47019.38 [#/sec]
Transfer rate: 48467.57 [Kbytes/sec]
Connection Times (ms)
min avg max std
Total: 0.0 0.3 54.1 0.2
Percentage of the requests served within a certain time (ms)
50% 0.3 ms
90% 0.4 ms
98% 0.6 ms
99% 0.7 ms
100% 54.1 ms
Run WARP and launch a mixed benchmark.
make benchmark
warp: Benchmark data written to "warp-mixed-2023-10-16[102354]-l70a.csv.zst"
Mixed operations.
Operation: DELETE, 10%, Concurrency: 20, Ran 4m59s.
* Throughput: 6.19 obj/s
Operation: GET, 45%, Concurrency: 20, Ran 5m0s.
* Throughput: 279.85 MiB/s, 27.99 obj/s
Operation: PUT, 15%, Concurrency: 20, Ran 5m0s.
* Throughput: 89.86 MiB/s, 8.99 obj/s
Operation: STAT, 30%, Concurrency: 20, Ran 5m0s.
* Throughput: 18.63 obj/s
Cluster Total: 369.74 MiB/s, 61.79 obj/s, 0 errors over 5m0s.
To see segmented request statistics, use the --analyze.v parameter.
warp analyze --analyze.v warp-mixed-2023-10-16[102354]-l70a.csv.zst
18642 operations loaded... Done!
Mixed operations.
----------------------------------------
Operation: DELETE - total: 1854, 10.0%, Concurrency: 20, Ran 5m0s, starting 2023-10-16 10:23:57.115 +0500 +05
* Throughput: 6.19 obj/s
Requests considered: 1855:
* Avg: 104ms, 50%: 30ms, 90%: 207ms, 99%: 1.355s, Fastest: 1ms, Slowest: 4.613s, StdDev: 320ms
----------------------------------------
Operation: GET - total: 8388, 45.3%, Size: 10485760 bytes. Concurrency: 20, Ran 5m0s, starting 2023-10-16 10:23:57.12 +0500 +05
* Throughput: 279.77 MiB/s, 27.98 obj/s
Requests considered: 8389:
* Avg: 221ms, 50%: 106ms, 90%: 492ms, 99%: 1.739s, Fastest: 8ms, Slowest: 8.633s, StdDev: 383ms
* TTFB: Avg: 81ms, Best: 2ms, 25th: 24ms, Median: 39ms, 75th: 65ms, 90th: 171ms, 99th: 669ms, Worst: 4.783s StdDev: 163ms
* First Access: Avg: 240ms, 50%: 105ms, 90%: 511ms, 99%: 2.08s, Fastest: 12ms, Slowest: 8.633s, StdDev: 480ms
* First Access TTFB: Avg: 88ms, Best: 2ms, 25th: 24ms, Median: 38ms, 75th: 64ms, 90th: 179ms, 99th: 919ms, Worst: 4.783s StdDev: 199ms
* Last Access: Avg: 219ms, 50%: 106ms, 90%: 463ms, 99%: 1.782s, Fastest: 9ms, Slowest: 8.633s, StdDev: 416ms
* Last Access TTFB: Avg: 81ms, Best: 2ms, 25th: 24ms, Median: 39ms, 75th: 65ms, 90th: 161ms, 99th: 657ms, Worst: 4.783s StdDev: 176ms
----------------------------------------
Operation: PUT - total: 2688, 14.5%, Size: 10485760 bytes. Concurrency: 20, Ran 5m0s, starting 2023-10-16 10:23:57.115 +0500 +05
* Throughput: 89.83 MiB/s, 8.98 obj/s
Requests considered: 2689:
* Avg: 1.165s, 50%: 878ms, 90%: 2.015s, 99%: 5.74s, Fastest: 99ms, Slowest: 8.264s, StdDev: 968ms
----------------------------------------
Operation: STAT - total: 5586, 30.2%, Concurrency: 20, Ran 5m0s, starting 2023-10-16 10:23:57.113 +0500 +05
* Throughput: 18.63 obj/s
Requests considered: 5587:
* Avg: 15ms, 50%: 11ms, 90%: 34ms, 99%: 80ms, Fastest: 0s, Slowest: 245ms, StdDev: 17ms
* First Access: Avg: 14ms, 50%: 10ms, 90%: 33ms, 99%: 69ms, Fastest: 0s, Slowest: 203ms, StdDev: 16ms
* Last Access: Avg: 15ms, 50%: 11ms, 90%: 34ms, 99%: 74ms, Fastest: 0s, Slowest: 203ms, StdDev: 17ms
Cluster Total: 369.64 MiB/s, 61.77 obj/s, 0 errors over 5m0s.
Total Errors:0.
Enterprise
For enterprise users, please visit seaweedfs.com for the SeaweedFS Enterprise Edition, which has a self-healing storage format with better data protection.
License
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
The text of this page is available for modification and reuse under the terms of the Creative Commons Attribution-Sharealike 3.0 Unported License and the GNU Free Documentation License (unversioned, with no invariant sections, front-cover texts, or back-cover texts).



