>>There is no reason to flush a restored disk until just the end, really. >>Issuing flushes every x MB could hurt other storages without need.
I'm curious to see host memory usage of a big local file storage restore (100GB), with writeback without any flush ? ----- Mail original ----- De: "Eneko Lacunza" <elacu...@binovo.es> À: "pve-devel" <pve-devel@pve.proxmox.com> Envoyé: Mardi 26 Juillet 2016 10:13:59 Objet: Re: [pve-devel] Speed up PVE Backup Hi, El 26/07/16 a las 10:04, Alexandre DERUMIER escribió: >>> I think qmrestore isn't issuing any flush request (until maybe the end), > Need to be checked! (but if I think we open restore block storage with > writeback, so I hope we send flush) > >>> so for ceph storage backend we should set >>> rbd_cache_writethrough_until_flush=false for better performance. > I think it's possible to pass theses flag in qemu block driver option, when > opening the rbd storage > > > http://docs.ceph.com/docs/hammer/rbd/qemu-rbd/ > > qemu-img {command} [options] > rbd:{pool-name}/{image-name}[@snapshot-name][:option1=value1][:option2=value2...] > > > > for qemu-img or with qemu drive option, I think it's possible to send as > option, ":rbd_cache_writethrough_until_flush=false" I developed a small patch to do this, waiting to test it in our setup (today or tomorrow) > But if missing flush if really the problem, it should be added to restore > command directly. (maybe 1 flush each 4MB for example) This flush is needed only for Ceph RBD, so I think using the flag above would be more correct. There is no reason to flush a restored disk until just the end, really. Issuing flushes every x MB could hurt other storages without need. In fact all this is because Ceph trying to "fix" broken virtio drivers... :) Thanks Eneko -- Zuzendari Teknikoa / Director Técnico Binovo IT Human Project, S.L. Telf. 943493611 943324914 Astigarraga bidea 2, planta 6 dcha., ofi. 3-2; 20180 Oiartzun (Gipuzkoa) www.binovo.es _______________________________________________ pve-devel mailing list pve-devel@pve.proxmox.com http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel _______________________________________________ pve-devel mailing list pve-devel@pve.proxmox.com http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
