Overview
iostat (sysstat package) shows CPU load and per-device I/O rates/utilization. Use it to find busy disks and whether the system is I/O-wait bound.
Syntax
iostat [options] [interval [count]]
iostat [options] [interval [count]] [device...]
Common Options
-x |
Extended device stats (%util, await, …) |
-z |
Skip idle devices |
-y |
Skip first (since-boot) report |
-d / -c |
Devices only / CPU only |
-h / -m / -k |
Human / MB / KB units |
-p |
Include partitions |
-t |
Timestamps |
-N |
Device-mapper names |
Key extended fields
r/s w/s |
Read/write requests per sec |
rkB/s wkB/s |
Throughput |
await |
Avg wait (queue + service) ms |
aqu-sz |
Avg queue length |
%util |
Device busy % (~saturation at 100% for simple devices) |
Examples with Explanations
Extended live
iostat -xz 1 5
iostat -xyz 1 10
Notes
- Install:
sudo apt install sysstat.
- First report without
-y is since boot; use interval mode for “now”.
- Multipath/RAID can make
%util interpretation subtler.