Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Thu, Oct 16, 2008 at 10:19:20AM +0200, Bart Coninckx wrote: > > fix your local io subsystem. > > fix your local io subsystem driver. > > > > check > > local io subsystem, > > (battery backed) write cache enabled? > > Yes, I did that yesterday, I got from 13 MB/Sec to 16 MB/Sec. Better, but > still not good. > > > raid resync/rebuild/re-whatever going on at the same time? > > nope, RAID has been built and is steady. > > > does the driver honor BIO_RW_SYNC? > > errr ... how can I check that? /proc/driver/cciss/cciss0 does not reveal > anything about that. > > > does the driver introduce additional latency > > because of ill-advised "optimizations"? > > I use a stock SLES 10 SP1 cciss driver. I did understand that the I/O > scheduler is not the best one. Perhaps you are referring to that? > > > if local io subsystem is ok, > > but DRBD costs more than a few percent in throughput, > > check your local io subsystem on the other node! > > That node is identical to the other one. > > > if that is ok as well, check network for throughput, > > latency and packet loss/retransmits. > > scp gives me about 70 MB/Sec, so my guess is that things are more likely > related to drbd and local io. scp does not know about fsync. use the same benchmark against drbd and non-drbd partition on that cciss... > > only if all of that seems ok too, > > check drbd configuration. > > > > > Of course, I am inclined to advise an upgrade to SP2, which might help > > > > with a newer cciss driver ;-) > > > > a-ha. > > since I use OES2 which is not supported on SP2, I'm somewhat reluctant on > installing the kernel from SP2. Novell support will most likely be gone when > I do this ... -- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. __ please don't Cc me, but send to list -- I'm subscribed