osd-scrub-least

Show the Ceph PGs whose last deep scrub is longest ago, and print the primary OSD (plus acting set).
Useful for spotting partitions that have not been deep-scrubbed for a while.

Features

• Parses both legacy "YYYY-MM-DD HH:MM:SS[.us]" and ISO-8601 timestamps with Z, +HH:MM, or +HHMM
• Works with ceph pg ls -f json and ceph pg dump_json across Ceph versions
• Deterministic sorting by oldest deep scrub first
• Option -n <NUM> to show the last N PGs (default: 5)
• --debug to show parsed epoch timestamps for verification

Requirements

• Perl 5.26+
• Ceph CLI on PATH with permissions to query PGs
• Perl modules:
  • Cpanel::JSON::XS
  • DateTime::Format::ISO8601
  • Try::Tiny
  • Getopt::Long (core)

Install on Debian/Ubuntu

apt update
apt install -y libcpanel-json-xs-perl libdatetime-format-iso8601-perl libtry-tiny-perl

Or via cpanm:

cpanm Cpanel::JSON::XS DateTime::Format::ISO8601 Try::Tiny

Usage

# default: show 5 oldest PGs
./osd-scrub-least.pl

# show 10 oldest
./osd-scrub-least.pl -n 10

# debug epoch parsing
./osd-scrub-least.pl --debug

Example output:

Top 5 PGs by oldest deep scrub:

PGID         Primary    Acting               Last Deep Scrub
----------------------------------------------------------------------
1.2f         osd.7      7,19,3              2025-07-14T03:12:45.123456Z
2.a3         osd.11     11,8,5              2025-07-15T08:02:17.457221+0000

How it works

• The script collects JSON from ceph pg ls -f json (preferred) or ceph pg dump_json (fallback).
• It extracts the PG array in a version-agnostic way (.pg_stats, .pg_map.pg_stats, .entries, or top-level array).
• Field last_deep_scrub_stamp is normalized:
  • Space is turned into T
  • Timezone +HHMM is normalized to +HH:MM
  • Missing timezone defaults to Z (UTC)
• Timestamps are parsed to epoch seconds. Missing/unknown becomes 0 and sorts first.
• Rows are sorted by ts ascending, with tie-breakers on the original stamp and pgid.

Exit codes

• 0 on success
• Non-zero when Ceph JSON cannot be read/parsed or no PGs are found

Notes

• If all timestamps are shown in ascending PGID order, enable --debug and check epochs.
  Usually this indicates a timestamp format that was not normalized. The script already handles +HHMM → +HH:MM, ISO Z, and space vs T.
• For machine-readable output (JSON/TSV), open an issue or extend the printing section.
  The data is already in structured form in @rows.