Mailing List Archive

XenServer 6.0 with DRBD very poor performance
Hi, I have two XenServers each with Dual Xeon E5320 @ 1.86Ghz, and 24 GB
RAM, 2, 2.0 Terabyte (Green drive) Westernal Digital HD. I am using the
XenServer 6.0 with latest version of DRBD. Both XenServers has
dedicated gigabit NIC (Intel) connected with Cat 6 patch cable (direct
connection), no switch used. i have enable jumbo frames (MTU 9000). Without
DRBD perforamnce are great, but I use DRBD, I am loosing more than 50% of
the performance. 1 MB sequential read is about 118 MB/s without DRBD, with
DRBD it is about 27 MB/s. I get very poor disk read/write. I have enabled
the tweak recommended by Linbit DRBD manual, still nothing seems to work. I
have also, played around with changing syncer rate, nothing helps. I am
using XenServer performance vm for testing the performance. Here is my DRBD
config, how can I speed things up. Please help !!!

# /etc/drbd.d/global_common.conf --------------------------------
global { usage-count yes; }
common {
protocol C;
net {
shared-secret "xenserver";
after-sb-0pri discard-zero-changes;
after-sb-1pri consensus;
after-sb-2pri disconnect;
max-buffers 8192;
max-epoch-size 8192;
sndbuf-size 1024k;
disk { max-bio-bvecs 1; }
handlers { split-brain "/usr/lib/drbd/"; }
syncer {rate 40M; al-extents 2099;}

# /etc/drbd.d/drbd-sr1.res --------------------------------------
resource drbd-sr1 {
device /dev/drbd1;
disk /dev/sdc;
meta-disk internal;
on Lab-Xen05 { address; }
on Lab-Xen06 { address; }