Error "Resource temporarily unavailable" occurs during slot migration by raw-key-value type.

[greatsharp]

Search before asking

• I had searched in the issues and found no similar issues.

Version

since 2.8

Minimal reproduce step

1. set migrate-type as raw-key-value
2. set migrate-batch-size-kb larger than 10240
3. set migrate-batch-rate-limit-mb larger than 64
4. migrate a lot of data in a slot-range.

What did you expect to see?

migrate success

What did you see instead?

migrate failed, error "Resource temporarily unavailable" occurs.

Anything Else?

No response

Are you willing to submit a PR?

• I'm willing to submit a PR!

[zhixinwen]

Not sure if we were seeing the same issue. In my case the error occurs before migration start:

[2025-09-17T23:10:15.395170+00:00][I][slot_migrate.cc:126] [migrate] Start migrating slot(s) 2 to 10.226.27.11:6379
[2025-09-17T23:10:15.395514+00:00][I][slot_migrate.cc:163] [migrate] Migrating slot(s): 2, dst_ip: 10.226.27.11, dst_port: 6379, max_speed: 4096, max_pipeline_size: 16
[2025-09-17T23:10:16.425408+00:00][E][slot_migrate.cc:195] [migrate] Failed to start migrating slot(s) 2. Error: failed to set import status on destination node: failed to check the response from the destination node: failed to read response: Resource temporarily unavailable
[2025-09-17T23:10:16.901209+00:00][I][slot_migrate.cc:248] [migrate] Failed to migrate a slot(s) 2
[2025-09-17T23:10:16.901245+00:00][I][slot_migrate.cc:472] [migrate] Clean resources of migrating slot(s) 2

[greatsharp]

take a loot at this PR: #3077

[zhixinwen]

Move the discussion in #3077 to this issue. Resource temporarily unavailable is due to 1s timeout set in checkMultipleResponses. In my case, I was seeing this issue because of RocksDB compaction stall freezes the whole event loop. The short term mitigation is:

1. Enable rocksdb.write_options.no_slowdown
2. Mitigate compaction slowness

For longer time:

1. Make timeout configurable
2. Add error retry mechanism so a single failure would not stop the whole slot migration