[DRBD-user] Sudden high CPU load

Richard Stockton drbd at richardleestockton.org
Wed May 18 04:09:50 CEST 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hi drbd folks,

We have been using DRBD with heartbeat for several years now.
The load averages on our RedHat servers have almost always stayed
below 1.0.  Suddenly last week the loads jumped up to 12-14 on
both servers.  They go down at night, when the usage goes down,
but by mid-day every business day they are back to 14.

We don't see anything out of the ordinary in logs, no drive
warning lights, no degraded RAID, nothing especially out of
bounds in iostat, NFS is running smoothly, tcpdump doesn't
show any nastiness (that we can see)....
We have run out of ideas.

Our setup is 2 disk arrays, with each server the fail-over for
the other.  These are POP/IMAP accounts with half the alphabet
on one server and half on the other.  If one server fails, the
other one takes over all of the alphabet.  Each letter is a
separate resource, with a separate IP, etc.  The size of the
letter partitions range from 5G to 120G.  The pop/imap servers
access the letters via NFS3.

RedHat 5.3 (2.6.18-128.1.10.el5)
DRBD 8.3.1
Heartbeat 2.1.4

Has anyone seen this sort of behavior before, and if so, what
the heck is happening?  We would appreciate any suggestions.

TIA,
  - Richard




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