Article ID: 119032, created on Dec 5, 2013, last review on May 5, 2014

  • Applies to:
  • Virtuozzo containers for Linux

Symptoms

vzstat tool permanently shows 0 for IOUSED and IOWAIT:

[root@brandy ~]# vzstat -o id,iowait,ioused -t -b
loadavg         0 0 0
CTNum           1
procs           293 1 292 0 0 0 0
CPU             0 0 0 0 100
sched latency   0 0
Mem             11874 10278 0
Mem latency     0 0
Swap            6007 6007 0.000 0.000
Net stats       0.024 43 0.000 0
Disks stats     0.000 0.000

  CTID IOWAIT IOUSED
100500   0.00   0.00

This happens only when queue scheduler is set to deadline:

[root@PCS ~]# cat /sys/block/sdX/queue/scheduler
noop anticipatory [deadline] cfq

Cause

This behavior is unexpected and has been recognized as a product bug, it's internal ID is PCLIN-32216.

Resolution

So far there is no workaround to see real IOUSED and IOWAIT values while scheduler set to "deadline". Bug will be fixed in one of the next product updates.

Search Words

IOWAIT

cfq

set iolimit

deadline

queue

PCLIN-32216

IOUSED

scheduler

e8e50b42231236b82df27684e7ec0beb 2897d76d56d2010f4e3a28f864d69223 d02f9caf3e11b191a38179103495106f

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