Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi all,
I recently installed DRBD 8.0.14-23 on two RHEL5 machines for use with
heartbeat, mysql, apache and so on.
The two machines are Sun xfire4140 with two quadcore 2.3 ghz AMD
opterons, 8 GB RAM each and are directly connected via two crossover
cables on gigabit lan using interface bonding (so it should be like a 2
gbit/s connection).
DRBD sits on a hardware raid 1 of two SAS harddrives. The drbd partition
is 75G in size.
Now I have some trouble with my applications that use MySQL (which
resides on the DRBD) being extremely slow.
My output from iostat suggests that the DRBD partition is very slow:
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz
avgqu-sz await svctm %util
sda 0.00 22.80 0.00 17.10 0.00 159.60 18.67 0.01 0.56 0.08 0.14
drbd0 0.00 0.00 0.00 26.80 0.00 107.20 8.00 3.60 134.46 37.26 99.85
The question now is where can I start looking for the issue of this? How can I tune performance?
Are there any special options in the drbd.conf I should look out for?
Thanks in advance,
Tobi
this is the output from /proc/drbd:
version: 8.0.14 (api:86/proto:86)
GIT-hash: bb447522fc9a87d0069b7e14f0234911ebdab0f7 build by bachbuilder@, 2008-12-19 22:49:51
0: cs:Connected st:Primary/Secondary ds:UpToDate/UpToDate C r---
ns:53981200 nr:1053428 dw:55034628 dr:154637 al:458 bm:208 lo:0 pe:2 ua:0 ap:1
resync: used:0/61 hits:65688 misses:104 starving:0 dirty:0 changed:104
act_log: used:1/257 hits:13494842 misses:464 starving:0 dirty:6 changed:458