Ceph

• 1:

sudo ceph osd getcrushmap -o crushmap.cm
sudo crushtool --decompile crushmap.cm -o crushmap.txt
sudo vim crushmap.txt
sudo crushtool --compile crushmap.txt -o new_crushmap.cm
sudo ceph osd setcrushmap -i new_crushmap.cm
sudo ceph -s

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Ceph infrastructure specification

Purpose

Describe the single-host Ceph CRUSH map maintained by infra/ceph and its documented operator workflow. This owner contains a map and documentation; its BUILD file exposes documentation, not a Ceph deployment target. The baseline describes checked-in source, not an observed running cluster.

Baseline revision: 550d7e79b1f5fdbc2b6017b75178471d6914082f. Observed: 2026-09-08. Sources: owner README, BUILD, and CRUSH map.

Requirements

Requirement: Single-host CRUSH topology

The maintained CRUSH map SHALL place four HDD devices, osd.0 through osd.3, in the host1 bucket beneath the default root, using the declared device weights and straw2 bucket algorithm.

Scenario: Inspect the recorded storage topology

• WHEN a maintainer reads the checked-in CRUSH map
• THEN all four OSDs belong to host1, and the default root contains that host
• AND this topology establishes a single-host placement baseline without asserting that the running cluster matches it

Requirement: OSD-level replicated and erasure placement

The maintained map SHALL define a replicated rule using chooseleaf firstn 0 type osd and an erasure rule using chooseleaf indep 0 type osd beneath the default root. The erasure rule SHALL set chooseleaf attempts to 5 and choose attempts to 100.

Scenario: Inspect the placement failure domain

• WHEN a maintainer evaluates replicated_rule or ceph-ec-data
• THEN placement selects OSDs within the recorded topology
• AND the map provides no requirement for replica separation across hosts

Requirement: Operator workflow documentation

The owner documentation SHALL describe exporting, decompiling, editing, compiling, and installing a CRUSH map followed by a Ceph status check. Executing that workflow MUST remain subject to the repository’s explicit infrastructure-operation authorization requirement.

Scenario: Use the documented map update procedure

• WHEN an authorized operator follows the map update instructions
• THEN the procedure obtains the current map before creating its compiled replacement and checks ceph -s after installation
• AND the presence of these instructions alone does not authorize a live map update