[READ] Monitor quorum: mons in/out of quorum and the monmap epoch.

Call this when health flags MON_DOWN or a clock-skew warn — it shows which monitors are actually holding quorum.

Args: target: Ceph target name from config; omit for the default.

[READ] Active mgr, its standbys, and the enabled mgr modules.

Args: target: Ceph target name from config; omit for the default.

[READ] Blocked/slow requests per OSD (decodes the SLOW_OPS health check).

Use this to find the OSD sitting on blocked ops when clients report stalls.

Args: target: Ceph target name from config; omit for the default.

[READ] Capacity usage + a deterministic days-to-nearfull projection.

Pass an observed daily growth in bytes to get daysToNearfull; without it the forecast is "insufficient-data". Nearfull is 85% of total. No clock is read — the projection is pure arithmetic.

Args: daily_growth_bytes: Observed daily growth in bytes; omit for a usage-only view. target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Tune osd_max_backfills / osd_recovery_max_active.

The #1 tuning ask: turn recovery/backfill down so a recovery storm stops starving client IO (or back up once it's calm). Reversible — records an undo restoring the prior config values.

Args: max_backfills: New osd_max_backfills value; omit to leave it unchanged. recovery_max_active: New osd_recovery_max_active value; omit to leave unchanged. target: Ceph target name from config; omit for the default.

[READ] Per-filesystem MDS ranks with the behind-on-trimming backpressure signal.

Surfaces each MDS rank's state, the client/standby counts, and the notorious "MDS behind on trimming" flag that quietly precedes metadata stalls.

Args: target: Ceph target name from config; omit for the default.

[READ] RGW daemons plus a large-omap (unsharded bucket index) scan.

Flags buckets whose index is unsharded/oversized — the LARGE_OMAP signal and the top RGW performance foot-gun. Partial-safe if the bucket call fails.

Args: target: Ceph target name from config; omit for the default.

[READ] HEALTH status with a plain-language cause + suggested action per active check.

Call this first on any "the cluster is unhealthy" question — it decodes raw HEALTH_WARN/ERR check codes (PG_DEGRADED, OSD_NEARFULL, …) into what's wrong and what to do next.

Args: target: Ceph target name from config; omit for the default.

[READ] Compact ceph -s summary: mons, OSDs up/in, PGs, usage, objects.

Args: target: Ceph target name from config; omit for the default.

[READ] All OSDs: up/in state, weight, host, device class.

Args: target: Ceph target name from config; omit for the default.

[READ] Per-OSD utilisation (most-full first) with near/backfill-full flags.

Args: target: Ceph target name from config; omit for the default.

[READ] Per-OSD commit/apply latency (slowest first) — find the slow disk.

Args: target: Ceph target name from config; omit for the default.

[WRITE][risk=low] Set/unset a cluster flag (noout/nobackfill/norecover/noscrub…).

Heavily used before maintenance (e.g. set noout while rebooting a host). Reversible — records an undo that toggles the flag back.

Args: flag: Flag name, e.g. "noout", "noscrub", "nobackfill", "norecover". enable: True to set the flag, False to clear it. target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Set an OSD's reweight (0.0 drains it). Reversible → prior weight.

Args: osd_id: Numeric OSD id (from osd_tree). weight: New reweight 0.0–1.0 (0.0 = full drain). target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Mark an OSD 'in' (return a drained/repaired OSD to service).

Args: osd_id: Numeric OSD id (from osd_tree). target: Ceph target name from config; omit for the default.

[WRITE][risk=high] Mark an OSD 'out' — drains its data (recovery storm / min_size risk).

Destructive to redundancy — pass dry_run=True to preview. Requires an approver (set CEPH_AUDIT_APPROVED_BY) under the graduated-autonomy policy.

Args: osd_id: Numeric OSD id (from osd_tree). dry_run: If True, preview without marking out. target: Ceph target name from config; omit for the default.

[WRITE][risk=high] Purge an OSD (destroy + crush rm + auth del). Irreversible.

Pass dry_run=True to preview. Requires an approver (CEPH_AUDIT_APPROVED_BY). Drain first (osd_reweight 0 → mark out → wait active+clean) before purging.

Args: osd_id: Numeric OSD id (from osd_tree). dry_run: If True, preview without purging. target: Ceph target name from config; omit for the default.

[READ] PG state histogram + every PG that is not active+clean.

Call this to answer "are my PGs healthy?" — it counts PGs by state and lists the ones needing attention.

Args: target: Ceph target name from config; omit for the default.

[READ] Stuck PGs (inactive/unclean/stale/undersized/degraded) with implicated OSDs.

Use this when a PG is not recovering — it surfaces the OSD ids to investigate.

Args: target: Ceph target name from config; omit for the default.

[READ] PGs overdue for shallow / deep scrub (decodes PG_NOT(_DEEP)_SCRUBBED).

Args: target: Ceph target name from config; omit for the default.

[WRITE][risk=low] Schedule a shallow scrub on a PG (clears a PG_NOT_SCRUBBED warn).

Args: pgid: Placement group id, e.g. "2.1a" (from pg_summary / scrub_status). target: Ceph target name from config; omit for the default.

[WRITE][risk=low] Schedule a deep (data-integrity) scrub on a PG.

Args: pgid: Placement group id, e.g. "2.1a" (from pg_summary / scrub_status). target: Ceph target name from config; omit for the default.

[READ] All pools: size/min_size, pg_num, autoscale mode, application, quota.

Args: target: Ceph target name from config; omit for the default.

[READ] Per-pool usage: used/avail bytes, percent, objects, usable capacity.

Args: target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Set a pool's byte/object quota. Reversible → prior quota.

Args: pool_name: Pool name (from pool_ls). max_bytes: New byte quota (0 clears it); omit to leave unchanged. max_objects: New object quota (0 clears it); omit to leave unchanged. target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Set a pool's pg_num. Reversible → prior pg_num.

Args: pool_name: Pool name (from pool_ls). pg_num: New placement-group count. target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Set a pool's PG autoscale mode (on/off/warn). Reversible → prior.

Args: pool_name: Pool name (from pool_ls). mode: Autoscale mode: "on", "off", or "warn". target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Create a replicated pool.

Args: pool_name: Name for the new pool. pg_num: Initial placement-group count (default 32). size: Replica count (default 3). application: Pool application tag: "rbd", "cephfs", or "rgw" (default "rbd"). target: Ceph target name from config; omit for the default.

[WRITE][risk=high] Set a pool's replica size — forces mass data movement on a live pool.

Pass dry_run=True to preview. Requires an approver (set CEPH_AUDIT_APPROVED_BY) under the graduated-autonomy policy. Reversible → prior size.

Args: pool_name: Pool name (from pool_ls). size: New replica count. dry_run: If True, preview without changing the size. target: Ceph target name from config; omit for the default.

[WRITE][risk=high] Delete a pool — destroys all of its data. Irreversible.

Pass dry_run=True to preview. Requires an approver (CEPH_AUDIT_APPROVED_BY). The classic footgun: there is no undo once the data is gone.

Args: pool_name: Pool name (from pool_ls). dry_run: If True, preview without deleting. target: Ceph target name from config; omit for the default.

[READ] RBD images (optionally one pool): size, features, snapshot count.

Args: pool: Restrict to a single pool name; omit for all pools. target: Ceph target name from config; omit for the default.

[WRITE][risk=medium] Create a new RBD image in a pool.

Args: pool_name: Pool the image lives in (from a pool listing). name: New image name. size_bytes: Image size in bytes. target: Ceph target name from config; omit for the default.

[WRITE][risk=low] Snapshot an RBD image. Reversible → delete the snapshot.

Args: pool_name: Pool the image lives in. image_name: Image to snapshot (from rbd_ls). snap_name: Name for the new snapshot. target: Ceph target name from config; omit for the default.

[WRITE][risk=high] Delete an RBD image and ALL its data. Irreversible.

Pass dry_run=True to preview. Requires an approver (CEPH_AUDIT_APPROVED_BY).

Args: pool_name: Pool the image lives in. image_name: Image to delete (from rbd_ls). dry_run: If True, preview without deleting. target: Ceph target name from config; omit for the default.

[WRITE][risk=high] Delete an RBD image snapshot. Irreversible.

Pass dry_run=True to preview. Requires an approver (CEPH_AUDIT_APPROVED_BY).

Args: pool_name: Pool the image lives in. image_name: Image the snapshot belongs to. snap_name: Snapshot to delete. dry_run: If True, preview without deleting. target: Ceph target name from config; omit for the default.