Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
listslut <listslut at ...> writes: > > I didn't set this cluster up but that information was documented by the > previous admin here: > > http://crunchtools.com/kvm-cluster-with-drbd-gfs2/ > > It is now to the point where provisioning space for a new VM is a day > long process with a load level that brings down the server. I did these > tests this morning. If the formatting gets really bad on send the non > drbd portion of the raid shows 2.14.79 MB writes and the drbd portion of > the raid shows 4.65MB to start and drops off to around 1.5MB average. > > Iostat test on the non drbd portion of the raid. > > Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn > cciss/c0d0 622.61 0.03 214.79 0 427 > drbd0 329.65 0.03 1.26 > 0 2 > > Iostat test on the drbd portion of the raid. > > Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn > cciss/c0d0 52.26 0.02 4.65 0 9 > drbd0 1182.41 0.02 4.65 0 9 > > Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn > cciss/c0d0 134.83 0.01 2.15 0 4 > drbd0 449.75 0.01 1.75 0 3 > > Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn > cciss/c0d0 105.00 0.00 1.60 0 3 > drbd0 407.00 0.00 1.59 0 3 > > Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn > cciss/c0d0 90.95 0.00 1.54 0 3 > drbd0 394.97 0.00 1.54 0 3 > > Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn > cciss/c0d0 114.93 0.00 1.68 0 3 > drbd0 430.35 0.00 1.68 0 3 > > Clustering was broken after an upgrade before I got here. I upgraded > both systems to the latest RHEL 5 about a month ago. The drbd was > compiled locally and is version drbd-8.2.6. > > Thank You > Ken > (Re-sending since my prior attempt via gmane doesn't appear to have worked; apologies if this is duplicated.) Hi, I'm seeing similar problems with massive underperformance on writes on my system. I'm running locally-compiled DRBD [version: 8.3.7 (api:88/ proto:86-91), GIT-hash: ea9e28dbff98e331a62bcbcc63a6135808fe2917] on RHEL 5. Read performance is fine, but I'm getting write throughput of about 4MB/s, with latency around 13ms (as measured with a script similar to the one in the user's guide). I haven't yet tried tuning various parameters in drbd.conf as described in the available performance-optimization guides, but it's so slow I have to think there must be some more fundamental problem at play here than a lack of optimization (i.e. the defaults shouldn't be *that* bad). And for what it's worth, I've ruled out the network link as a possible bottleneck -- it's giving me 1.97Gbps throughput in both directions according to iperf (a bonded pair of back-to-back GbE ports, 9k MTU). Anyone have any suggestions or advice? Thanks, Zev