# pgCluu 5.0 adds PostgreSQL I/O stats, cgroup limits and kernel pressure reports

> **Key takeaway:** pgCluu 5.0 introduces detailed I/O statistics collection from pg_stat_io, postmaster process limits including cgroup v2 constraints, and kernel pressure stall information for PostgreSQL performance auditing.

**Published:** 2026-10-22T00:00:00+00:00 
**Source:** PostgreSQL Official News 
**Category:** databases-storage 
**Canonical URL:** https://fosswire.org/news/pgcluu-50-adds-postgresql-io-stats-cgroup-limits-and-kernel-.html 

## Summary
pgCluu 5.0, a Perl-based PostgreSQL cluster auditing tool, has been released with expanded system-level visibility. The update adds collection of I/O statistics via pg_stat_io for PostgreSQL 16+, reports on replication slots and pg_hba_file_rules, and tracks postmaster process limits including cgroup v2 memory, CPU and I/O quotas. It also introduces kernel pressure stall information (PSI) reporting and memory events for both the host and PostgreSQL's cgroup.

## What's new in pgCluu 5.0
- **I/O statistics**: Collects from pg_stat_io (PostgreSQL 16+), with reports for throughput per backend type, shared buffers, WAL I/O, temporary relations I/O, and async I/O (PostgreSQL 18+)
- **Postmaster limits**: Tracks oom_score_adj, file/process/memory limits, and cgroup v2 constraints (memory.max, cpu.max, io.max, pids.max) plus v1 quotas
- **Kernel parameters**: Expanded collection to include vm.dirty_*, NUMA settings, transparent hugepage shmem config, block device tunables, and CPU frequency governor data
- **Pressure stall information**: Reports CPU/memory/I/O pressure percentages for both host and PostgreSQL cgroup via /proc/pressure (kernel 4.20+)
- **Memory events**: Tracks cgroup memory.events (high, max, oom, oom_kill) and /proc/vmstat counters including allocstall, compaction, and page cache refaults

## Why it matters
The expanded kernel and cgroup visibility helps database administrators diagnose resource contention and OOM-related stability issues in containerized or tightly regulated production environments.