We used to use CLVM a while ago before we shifted to Ceph. Cluster suite/corosync was a bit of a nightmare, and fencing events caused all sorts of locking (DLM) problems. I helped a CloudStack user out a couple of month ago, after they upgraded and CLVM broke, so I know it's still out there in limited places. I wouldn't recommend using it today unless you're very brave and have the capability of troubleshooting the code yourself.
-Si ________________________________ From: Wido den Hollander <w...@widodh.nl> Sent: Thursday, January 21, 2021 11:26 AM To: d...@cloudstack.apache.org <d...@cloudstack.apache.org>; n...@li.nux.ro <n...@li.nux.ro> Cc: users@cloudstack.apache.org <users@cloudstack.apache.org> Subject: Re: Experiences with KVM, iSCSI and OCFS2 (SharedMountPoint) On 21/01/2021 11:34, n...@li.nux.ro wrote: > Hi, > > I used SharedMountPoint a very long time ago with GlusterFS before > Cloudstack had native integration. > Don't remember the details, but overall my impression was that it worked > surprisingly well, of course back then there weren't as many feature, so > less stuff to test. I would give it a go. > > As a side note, I did also use iSCSI with CLVM with success, it was > quite fast. I ended up doing it because it was difficult to get OCFS > running on EL6 and GFS2 had a reputation for being very slow. Marcus has > a lot of experience with this, might want to get in touch with him: > https://www.slideshare.net/MarcusLSorensen/cloud-stack-clvm I assume you used CLVM with Corosync? My concern with LVM is: - No thin provisioning (when used with CloudStack) - No snapshots (Right?) - Not very much used OCFS2 doesn't have my preference either, but otherwise you have to use corosync. Anybody else otherwise using CLVM? Wido > > HTH, > Lucian > > On 2021-01-21 09:32, Wido den Hollander wrote: >> Hi, >> >> For a specific use-case I'm looking into the possibility to use iSCSI >> in combination with KVM. >> >> Use-case: Low-latenc I/O with 4k blocks and QD=1 >> >> KVM with CloudStack doesn't support iSCSI natively and the docs and >> other blogs refer to using 'SharedMountPoint' with OCFS2 or GFS2: >> >> - >> http://docs.cloudstack.apache.org/en/latest/adminguide/storage.html#hypervisor-support-for-primary-storage >> >> - >> https://www.shapeblue.com/installing-and-configuring-an-ocfs2-clustered-file-system/ >> >> >> It has been a really long time since I've used OCFS2 and I wanted to >> see what experiences from other people are. >> >> How is the stability and performance of OFCS2? It seems that >> performance should be rather good as lock/s is a problem with >> clustered filesystems, but since we only lock the QCOW2 file on boot >> of the VM that shouldn't be an issue. >> >> In addition to OCFS2, how mature is 'SharedMountPoint' as a storage >> pool with KVM. Does is support all the features NFS supports? >> >> Thanks, >> >> Wido
