Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi,
I'm attempting to build a redundant storage solution using drbd replication,
however I can't seem to get the performance I would have expected.
I have the two servers on an Infiniband link, which has tested at about
170MB/s
(Megabytes not Megabits) with netcat (CPU bound).
Both disks write at just under 100MB/s (tested via dd). Yet when attempting
to
write to the drbd device on the primary I consistently get 30MB/s. I assume
the problem must be something I've configured incorrectly, but for the life
of
me I can't figure out what it is.
My configuration can be found at: http://pastie.org/737624
I have tried Google, and read and played with the tuning recommendations
in the drbd manual, with no success. In an effort to demonstrate the
problem is not network speeds, or the secondary, I have brought down the
secondary, and still see the same performance:
[root at lager ~]# cat /proc/drbd
version: 8.3.2 (api:88/proto:86-90)
GIT-hash: dd7985327f146f33b86d4bff5ca8c94234ce840e build by
mockbuild at v20z-x86-64.home.local, 2009-08-29 14:07:55
1: cs:WFConnection ro:Primary/Unknown ds:UpToDate/DUnknown C r----
ns:1048576 nr:0 dw:0 dr:1048576 al:0 bm:64 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b
oos:0
[root at lager ~]# dd if=/dev/zero of=/dev/drbd1 bs=512M count=2
2+0 records in
2+0 records out
1073741824 bytes (1.1 GB) copied, 32.6865 seconds, 32.8 MB/s
[root at lager ~]# drbdadm down r0
[root at lager ~]# dd if=/dev/zero of=/dev/sda2 bs=512M count=2
2+0 records in
2+0 records out
1073741824 bytes (1.1 GB) copied, 11.1106 seconds, 96.6 MB/s
If anyone has any suggestions as to how I can troubleshoot this further it
would be greatly appreciated.
Thanks!
Walton
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