[DRBD-user] Terrible Performace on 1 server only drbd 8.3.1

808blogger 808blogger at gmail.com
Wed Aug 12 03:49:33 CEST 2009

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


I use drbd alot. 

I have a strange issue, I get terrible performace from drbd on 1 physical
Right now i have the drbd split and am running just the one node detached I
have made it a primary and mounted it to test. I have moved the syncer rate
from 5M to 50M. and nothing makes a difference. 

When i do lots of writes to drbd mount i get massive load spike all the way
to 4.00 and then the drbd becomes unusably slow for up to 1 hour until it
settles down again.

the physical hw is a dual core xeon 3ghz with 10gb ram and perc5 controller
i have 2 containers on the raid(perc5)  /dev/sda and /dev/sdb
both containers use all 4 disks in the raid

writes to /dev/sda  are totally normal 
/dev/sdb is for the drbd and those writes cause the load to spike. ONLY when
using DRBD 

The other side of this (detached) cluster is NOT having the load issues and
has slightly newer hardware.

However i have run storage clusters with way less power than this machine
with no trouble at all using drbd.

When this occurring i get lots of wa% on the CPU's. Any guidance or hints
would be appreciated

I know this /proc/drbd shows a bunch of oos: but thats because i stopped a

# cat /proc/drbd 
version: 8.3.1 (api:88/proto:86-89)
GIT-hash: fd40f4a8f9104941537d1afc8521e584a6d3003c build by
pavel at xemulnb.sw.ru, 2009-05-22 16:02:49
 0: cs:StandAlone ro:Primary/Unknown ds:UpToDate/Outdated   r----
    ns:0 nr:0 dw:640576 dr:639685 al:187 bm:60 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b

/etc/drbd.conf   (super minimal at this point)

global { usage-count yes; }
common { syncer { rate 50M; } }
resource r0 {
  protocol C;
    device     /dev/drbd0;
    disk       /dev/sdb1;
    meta-disk  internal;

  on none {
    device     /dev/drbd0;
    disk       /dev/sdb1;
    meta-disk  internal;


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