Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
> > > 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 ... All, I updated the cciss-driver from 3.6.14 to 3.6.18-17. Unfortunately this didn't get me any better results. So this is not related to driver issues I guess. Next I will try to change the I/O scheduler. Any other suggestions? Thx, B.