Background read-only region creation#1919
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When the Crucible Agent is requested to create a read-only region from a remote Downstairs source, this currently blocks the worker thread as region creation is performed in the worker loop, and it cannot respond to other state changes. This commit spawns region creation threads that the main worker thread can send requests to, and sends all read-only region creation requests there. This builds on the previous work to separate the serialized on-disk types from the in-memory types: a `Creating` state is added to the in-memory type and used while this background creation is occurring.
leftwo
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Apr 10, 2026
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Thanks for the work here, I have some questions for you.
| let log0 = log.new(o!("component" => "worker")); | ||
| let df0 = Arc::clone(&df); | ||
| std::thread::spawn(|| { | ||
| tokio::spawn(async { |
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If we are going from a real thread to a tokio task, could a long running region create trip us up here? The old way was with a thread which seemed like it could go off and do whatever for an hour and the rest of the agent could continue working. Do we run any risk of that here?
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I'm not sure about all the differences between threads and tasks, but I don't think there's a risk. With worker running in a thread or with a task, the read/write region creation occurs separately from the dropshot server and datafile manipulation logic.
leftwo
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Apr 14, 2026
jmpesp
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May 26, 2026
Update Crucible from `7103cd3a` to `bd9a0e2a`, picking up the following PRs: - Use an explicit rev for oxidecomputer git deps (oxidecomputer/crucible#1936) - Add Clone and Deserialize to VolumeInfo et al (oxidecomputer/crucible#1935) - Update omicron/oximeter (oxidecomputer/crucible#1933) - [meta] update to drift 0.1.4 (oxidecomputer/crucible#1932) - Don't log if there is nothing to log (oxidecomputer/crucible#1930) - Add VolumeInfo (oxidecomputer/crucible#1928) - Remove bonus Volume layer (oxidecomputer/crucible#1927) - Add session and client id to panic messages (oxidecomputer/crucible#1926) - [crucible-agent-types] migrate to RFD 619 pattern (oxidecomputer/crucible#1899) - Background read-only region creation (oxidecomputer/crucible#1919) - [crucible-downstairs-repair] switch to RFD 619 pattern (oxidecomputer/crucible#1901) - [crucible-pantry] switch to RFD 619 pattern (oxidecomputer/crucible#1900) - Use separate in-memory types (oxidecomputer/crucible#1913) - Remove old field from dtrace action script (oxidecomputer/crucible#1917) - Retry data writes that return an IO error (oxidecomputer/crucible#1915) - Bump dropshot to 0.17.0 (oxidecomputer/crucible#1909) - Reject snapshot requests when read-only (oxidecomputer/crucible#1914) - update ringbuf method, fix clippy lint (oxidecomputer/crucible#1904) - bump vergen-v9 version too (oxidecomputer/crucible#1903) - update dropshot to 0.16.7, dropshot-api-manager to 0.5.2 (oxidecomputer/crucible#1851) - perf-vol.d updates (oxidecomputer/crucible#1898) - upgrade progenitor to 0.13, reqwest to 0.13 (oxidecomputer/crucible#1854) - Remove cargo nextest from github workflow, out of space (oxidecomputer/crucible#1846) - Add a test for VCR serialize/deserialize (oxidecomputer/crucible#1843) Update Propolis from `bc489ddf` to `58ab73bd`, picking up the following PRs: - Bump crucible to latest, update Omicron, use explicit revs (oxidecomputer/propolis#1141) - Add project and silo ids to VM attestation (oxidecomputer/propolis#1114) - Update escargot (oxidecomputer/propolis#1139) - Prefix shebang and mark D scripts as executable (oxidecomputer/propolis#1140) - Fix error in propolis-server README (oxidecomputer/propolis#1138) - [meta] update to drift 0.1.4 (oxidecomputer/propolis#1137) - Fix Intel CPUID leaf 4 cache topology for SMT (oxidecomputer/propolis#1002) - support NVMe Deallocate (oxidecomputer/propolis#1105) - viona: do not lose used/avail indices (oxidecomputer/propolis#1135) - viona: multiqueue device should stay multiqueue across migration (oxidecomputer/propolis#1121) - Bump crucible rev to latest (oxidecomputer/propolis#1132) - expand zerocopy IntoBytes/FromByes use in guest memory accesses (oxidecomputer/propolis#1130) - dropshot-api-manager 0.7.1 (oxidecomputer/propolis#1129) - improve slog component setting (oxidecomputer/propolis#1124) - wait for viona Poller to run before declaring device running (oxidecomputer/propolis#1118) - virtio: tolerate importing queues with adjusted size (oxidecomputer/propolis#1117) - Run viona unit tests in CI (oxidecomputer/propolis#1120) - feature gate Crucible-specific boot digest code (oxidecomputer/propolis#1119) Also: - ran `cargo update -p vergen` - removed the `reqwest012` dependency - removed `reqwest012_client` from Nexus - ran `cargo hakari generate` and `cargo hakari manage-deps` - replace use of `ProgenitorOperationRetry` with `retry_operation_while_indefinitely` - during the region replacement drive saga, consume the new `VolumeInfo` from Propolis and use that to determine when to consider a replacement done
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When the Crucible Agent is requested to create a read-only region from a remote Downstairs source, this currently blocks the worker thread as region creation is performed in the worker loop, and it cannot respond to other state changes.
This commit spawns region creation threads that the main worker thread can send requests to, and sends all read-only region creation requests there.
This builds on the previous work to separate the serialized on-disk types from the in-memory types: a
Creatingstate is added to the in-memory type and used while this background creation is occurring.