Keith, I'm not sure it's a good idea, however the first thing to avoid is to present the replicated disk space to your virtualized peers as vDisks on a VMFS. Use RDMs instead, in physical mode if possible, to grab some more perfs. Then for this RDM, use a vdisk node that will cause the instantiation of a new vSCSI adapter (not the 0:1 default, but rather 1:0 for instance). It will probably create an LSI Logic Parallel virtual adapter, change it to the vmware paravirtual scsi driver, it will help a lot too. Then, not sure it has a big impact on DRBD but VMware can generate IOs up to 32MB. It's a known perf issue for midrange storage arrays such as HP EVAs (and even EMC Clariions I guess) causing big slowdowns due to IO segmentation handling by the storage processors, we use to reduce it to 64k or 128k instead. Again, I'm not sure it would have an impact on DRBD, may be the gurus can give their advices about that ? Would it even make sense to decrease it to 4K since DRBD chuncks are 4K large ? Or is it another part of the kernel storage chain that's in charge of handling large IOs segmentation, in which case we don't mind at all from the DRBD standpoint... Then what else ? I think that's all. I will think of it a bit more and let you know if something comes up. BTW, the physical storage space intend to replicate is local storage, right ? Or shared external storage device ?
Regards, Pascal. -----Message d'origine----- De : drbd-user-boun...@lists.linbit.com [mailto:drbd-user-boun...@lists.linbit.com] De la part de Keith Christian Envoyé : mercredi 23 mai 2012 17:29 À : drbd-user@lists.linbit.com Objet : [DRBD-user] Moving a DRBD cluster from physical machines to VMWare machines Looking for guidance from Linbit, or the list, about DRBD's disks remaining on two separate physical servers, except that the peer servers are virtualized? For instance: Writes of approximately 18,000 blocks per second for the busy hours, as reported by SAR. How much a performance hit is there with the same hardware after VMWare is in the picture? (I'm sure there are VMWare config settings to optimize disk reads/writes for an application like DRBD.) Thanks. =====Keith _______________________________________________ drbd-user mailing list drbd-user@lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user _______________________________________________ drbd-user mailing list drbd-user@lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user
