Resharding

The storage-api-reshard utility explores moving data from N old shards to M new shards, where M, N is the full shards count on installation. To get the information about command line parameters for storage-api-reshard utility, run the following command:

docker run --rm -ti --entrypoint "/storage-api-reshard" docker.int.ntl/ntech/universe/sf-api:ffserver-11.240325 --help

The most important command line flags are the following:

Command line flags	Type	Description
-config	string	Path to config file.
-config-template	–	Output config template and exit.
-delete-old	–	Delete migrated faces on old shard (default true).
-dry-run	–	Do not add/delete faces, perform only read requests (default true).
-gallery	string	Gallery to reshard (default “history”).
-help	–	Print help information.
-max-face-id	uint	Max object id for execution (default 18446744073709551615).
-min-face-id	uint	Min object id for execution.
-new-shards	[]string	List of new shards url.
-old-shards	[]string	List of old shards url.
-shard-idx	int	Execute migration for old_shards[idx]. Required parameter. On one execution only 1 old shard can be migrated to new shards.

Warning

It’s recommended to create a dump before resharding.

To run the storage-api-reshard utility, do the following:

1. Create a default storage-api-reshard configuration file.

   docker run --rm -ti --entrypoint "/storage-api-reshard" docker.int.ntl/ntech/universe/sf-api:ffserver-11.240325 \
       --config-template > /opt/ffserver/configs/storage-api-reshard.yaml
   

   • /opt/ffserver/configs/: the directory on the host to store the configuration file.

2. Modify configuration file:

   ...
   gallery: history
   min_face_id: 0
   max_face_id: 18446744073709551615
   shard_idx: 0
   dry_run: true
   delete_old: true
   old_shards:
   - http://tnt-1-1:8001/v2/
   - http://tnt-2-1:8001/v2/
   new_shards: []
   - http://tnt-1-1:8001/v2/
   - http://tnt-2-1:8001/v2/
   - http://tnt-3-1:8001/v2/
   ...
   

   Important

   storage-api-resharder makes decisions based solely on shard number, so the new_shards list should be either shortened version of old_shards when scaling down, or the same as old_shards plus a few new lines when scaling up.

3. Run storage-api-reshard utility with the configuration file in dry_run to check your configuration.

   docker run --rm -ti --network server --entrypoint "/storage-api-reshard" \
       --volume /opt/ffserver/configs/storage-api-reshard.yaml:/storage-api-reshard.yaml \
       docker.int.ntl/ntech/universe/sf-api:ffserver-11.240325 \
       --config /storage-api-reshard.yaml
   

   Console output:

   Config:
   ---
   gallery: face:test
   min_face_id: 0
   max_face_id: 18446744073709551615
   shard_idx: 0
   dry_run: true
   delete_old: true
   old_shards:
   - http://tnt-1-1:8001/v2
   - http://tnt-2-1:8001/v2
   new_shards:
   - http://tnt-1-1:8001/v2
   - http://tnt-2-1:8001/v2
   - http://tnt-3-1:8001/v2
   ...
   2024/06/06 06:58:47 SAR-BpLnfgDs | got faces(4 ... 6), will migrate 3/3
   2024/06/06 06:58:47 SAR-BpLnfgDs | total:3 migrated:3 migrateRatio:1.00 duration:0.00s speed:2138.16/s
   
   2024/06/06 06:58:47 Done
   

4. Run the storage-api-reshard utility with the configuration file without dry_run mode for all shard idx for migration.