Jed Reynolds wrote: > My NFS setup is a heartbeat setup on two servers running Active/Passive > DRBD. The NFS servers themselves are 1x 2 core Opterons with 8G ram and > 5TB space with 16 drives and a 3ware controller. They're connected to a > HP procurve switch with bonded ethernet. The sync-rates between the two > DRBD nodes seem to safely reach 200Mbps or better. The processors on the > active NFS servers run with a load of 0.2, so it seems mighty healthy. > Until I do a serious backup. > > I have a few load balanced web nodes and two database nodes as NFS > clients. When I start backing up my database to a mounted NFS partition, > a plain rsync drives the NFS box through the roof and forces a failover. > I can do my backup using --bwlimit=1500, but then I'm not anywhere close > to a fast backup, just 1.5MBps. My backups are probably 40G. (The > database has fast disks and between database copies I see run at up to > 60MBps - close to 500Mbps). I obviously do not have a networking issue. > > The processor loads up like this: > bwlimit 1500 load 2.3 > bwlimit 2500 load 3.5 > bwlimit 4500 load 5.5+ > > The DRBD secondary seems to run at about 1/2 the load of the primary. > > What I'm wondering is--why is this thing *so* load sensitive? Is it > DRBD? Is it NFS? I'm guessing that since I only have two cores in the > NFS boxes that a prolonged transfer makes NFS dominates 1 core and DRBD > dominate the next, and so I'm saturating my processor. Is your CPU usage 100% all the time? Can you send us the output of vmstat -n 5 5 when you're doing a backup? Regards, Ugo