Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Jan Kellermann|werk21 wrote: > Dear Gabriele, > > we are running a similar system on RHEL5 (xen over drbd over lvm) and > have not this problem. the drbd is 8.2. > > Did you test writing in split-brain-situation without xen? > Maybe the drbd is a little "to hard" configured so that it throw a > panic in case of unsync. Then xen has no chance to work further. > In drbd.conf are a lot of parameters for that issue... I have tested the writing in a split-brain-situation with the drbd devices mounted and it works as it should. > > Or it may be a problem, how xen is including the disks. What path is > in your domu-conf? We use "drbd:ressourcename", so drbd will manage > all for xen. > Have a look: > http://fghaas.wordpress.com/2007/09/03/drbd-806-brings-full-live-migration-for-xen-on-drbd/ > I use the drbd rpm that comes with SLES10 and unfortunately it's not drbd8x, so I can't use the new drbdresourcename parameter. If I try to use it the Xen host sees it as a file and not a block device. > > I have an other issue: On your system we have big trouble with iowait. > The disks are high performant in a raid5. The iovalues are very good. > But in domu we have iowaits up to 80% (e.g. while rsync or bzip). May > you tell me your experience? Because we are not able to narrow the > problem down at the time. I'm sorry but I can't help you with the iowait problem since I really haven't had a chance to implement my setup yet. > > Regards to lund (jealous of midsommar...) > Jan Kellermann > > > Gabriele kalus schrieb: >> I don’t know if this is a drbd or a xen issue so I will post this on >> both lists. >> >> I have 2 HP Proliant servers with SLES10 SP2 installed. There are 8 >> disks on the system, 2 of the disks are in a hardware raid1 and the >> rest is raid5, also hardware. The servers have several network cards; >> one is exclusively for drbd replication. I use the drbd 0.7.22-42 >> that ships with SLES10 and kernel 2.6.16.60-0.23-xen. >> >> The Xen host is installed on a non-lvm2 partition of 20 GB on the >> raid1. The rest of the raid1 are a volume group called system. I have >> several logical volumes on the volume group system, called mail-root, >> mail-swap, webmail-root, webmail-swap, etc. The *-root lvs are to be >> the drbd devices where the domUs systems are going to be installed. >> The *-swap are just for swap which I don’t want to replicate. >> >> I have tested the setup without the domUs running but with mounted >> drbd devices and pulled the network cable that manages the >> replication. Everything works as it should; both servers continue >> working and replication starts as soon as I connect the cable again. >> >> I have tested to install the domUs on file systems on the drbd >> devices, i.e. with the drbd devices mounted and it also works as it >> should. >> >> But when I install the domUs on physical devices /dev/drbdx for the >> domUs and pull the network cable between the replicating nics the Xen >> host with the domUs running hangs. Only a cold boot gets it started >> again. The replication works as it should as long as the cable is >> there or as long as both servers are up, everything gets replicated >> through the dedicated nic. But if I reboot the passive server the >> active server hangs, i.e. the same situation as when I pull the >> network cable. I have all the domUs on one of the servers, the other >> server is just passive. >> >> I haven't installed heart beat to avoid adding complexity to the >> situation. >> >> Can somebody help me figure out why it I can’t get it to work when >> the domUs are installed on physical devices? >> >> Regards >> >> Gabriele >> > -- Gabriele Kalus, Ph.D. IT-Manager Lund University, Physics Department Box 118 SE-22100 Lund, SWEDEN Phone: +46-462229675 Mobil: 0702-901227 Fax: +46-462224709