Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Le 08/11/2012 12:52, Felix Frank a écrit : > Hi, > > On 11/08/2012 12:18 PM, "[SOLTECSIS] Carles Xavier Munyoz Baldó" wrote: >> Hi, >> We are creating a PROXMOX 2 cluster using DRBD and we have doubts about >> which of the next options is better: >> (A) DRBD over LVM. >> (B) DRBD as a PV for LVM. >> >> Which is the best option? >> >> I remember that I have read that DRBD over LVM is not a recomended >> configuration, but I don't remember why. I believe that I have readed >> that in the DRBD documentation itself, but I'm not able to find it now. >> >> Anyone knows if exists any kind of problem using DRBD over LVM? > > it does work :-) > > I'm not at all sure what's better performance-wise. > > If your backing device is an LV, you do incur a write penalty to all > drbd interactions on both nodes. > Still, that doesn't mean that the setup will be slower than the other > way around. > > It's usually a good idea to make your own tests, hopefully with a most > befitting workload. I've been digging into this issue recently. There is some drbd documentation with this scenario (http://www.drbd.org/users-guide/s-lvm-lv-as-drbd-backing-dev.html), and I have done such setup in the past. It does work, but I was wondering if it is safe? DRBD by default make use of barrier (unless no-disk-barrier is set with a BBU RAID backend), and such barrier where not correctly implemented in LVM before kernel 2.6.33. So I guess there are some cases where there is problems, eg. with software MD raid. Cheers, Denis > > Cheers, > Felix > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > -- Denis Cardon Tranquil IT Systems Les Espaces Jules Verne, bâtiment A 12 avenue Jules Verne 44230 Saint Sébastien sur Loire tel : +33 (0) 188.8.131.52.55 http://www.tranquil-it-systems.fr