Re: [ovirt-users] Storage questions

On Wed, Nov 23, 2016 at 1:18 PM, Oscar Segarra <oscar.segarra(a)gmail.com&gt; wrote: > Hi, >> >> As on oVirt is it possible to attach local storage I supose it can be >> used to run virtual machines: >> >> I have drawn a couple of diagrams in order to know if is it possible to >> set up this configuration: >> >> 1.- In on-going scenario: >> Every host runs 100 vdi virtual machines whose disks are placed on local >> storage. There is a common gluster volume shared between all nodes. >> >> [image: Imágenes integradas 1] >> > > With local storage you end up losing many of the benefits of shared > storage - including migration and HA. > If you do have SSD on your physical hosts, have you considered building > gluster volume using these? This could give you improved performance. > Regarding performance, I think it is best that you run a test comparing > gluster storage performance with local storage and see if this is > acceptable to you. Please share the results in case you do. > > Yes, but I want to avoid possible corruption problems due to possible > unrecoverable gluster bugs. > We have to make some developement and I don't want to spend money in this > process and then discover that the performance is not good enought and have > to do a > "possible unrecoverable gluster bugs" is a sweeping statement. Do you have any particular issue that you can refer us to? > > > In the above diagram each host is in its own cluster - as all hosts in a > cluster should have access to the storage domain? > > Yes, every host has ho have access to two storage domains: The local one > and the shared gluster one. > > Is the gluster volume for backup served from a separate set of server? > > No, each host will have 2 disks /dev/sdb1 (for runing vm on local > storage) and /dev/sdc1 (for shared gluster where store backups) > > >> >> 2.- If one node fails: >> >> [image: Imágenes integradas 2] >> >> oVirt has to be able to inventory the copy of machines (in our example >> vdi201 ... vdi300) and start them on remaining nodes. >> >> ¿Is it possible to reach this configuration with oVirt? ¿or something >> similar? >> > > This is the use case for gluster volume shared storage - where volume is > a replica 3. If any host goes down, the data is available on the remaining > 2 nodes, and the VMs can be migrated to other nodes. > > Yes, I know, but I'm already worried about corruption issues due to > possible gluster bugs or performance problems under heavy load. > > I don't think what you ask for is possible automatically. If you want > local storage to gluster volume backup, you would need 1-1 mapping. i.e > each local storage domain has its own gluster volume backup.You could then > import the storage domain that's backed up on the gluster volume and start > the VMs on the remaining hosts. > > I don't want local storage for backup, I prefer gluster shared storage > for backup. > > >> Making backup with the import-export procedure based on snapshot can >> take lot of time and resources. Incremental rsync is cheaper in terms of >> resources. >> > > Geo-replication based backup internally uses rsync, it also takes into > account that VM images are consistent on disk before being synced. It > however works as a backup option between two gluster volumes. > > Do you know if is it possible to have multiple masters geo-replicating > against a single slave? > No it is not possible. A master can have multiple slaves not the other way around. > > Thanks a lot. >