Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 2008-10-14T18:32:50, Bart Coninckx <bart.coninckx at telenet.be> wrote: > Hi all, > > I previously posted about a sync going somewhat slow (managed to get it up to > 18MB/sec). > I figured this could be just the syncing, so I decided to do some performance > tests as mentionned in the webinar. > > I used: > dd if=/dev/zero of=/dev/drbd0 bs=1G count=1 oflag=direct oflag=direct uses direct sync'ing (obviously), which means there's not very much optimization going on. bs=1G also means that a huge memory block is allocated and flushed. So at least these parameters are far from sane - bs=16384 oflag=fsync might provide better performance. The next step might be to check whether you're using internal meta-data, which also might not exactly perform very well (seek time issues). > The server is a HP ML370 G5 with a 1TB RAID-5 setup. The controller used the > cciss driver. DRBD is 0.7.22. OS is SLES 10 SP1. The network link is gigabit, > full duplex, set to 1000 Mbit. Of course, I am inclined to advise an upgrade to SP2, which might help with a newer cciss driver ;-) > I plan to enable write back cache, but I wonder if that is going to make THE > difference. If you're using internal metadata, that is going to make a huge difference. Regards, Lars -- Teamlead Kernel, SuSE Labs, Research and Development SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg) "Experience is the name everyone gives to their mistakes." -- Oscar Wilde