On March 28, 2020 11:03:54 AM GMT+02:00, Gianluca Cecchi <gianluca.cec...@gmail.com> wrote: >On Sat, Mar 28, 2020 at 8:39 AM Strahil Nikolov <hunter86...@yahoo.com> >wrote: > >> On March 28, 2020 3:21:45 AM GMT+02:00, Gianluca Cecchi < >> gianluca.cec...@gmail.com> wrote: >> >> >[snip] > >>Actually it only happened with empty disk (thin provisioned) and >sudden >> >high I/O during the initial phase of install of the OS; it didn't >> >happened >> >then during normal operaton (even with 600MB/s of throughput). >> > >[snip] > > >> Hi Gianluca, >> >> Is it happening to machines with preallocated disks or on machines >with >> thin disks ? >> >> Best Regards, >> Strahil Nikolov >> > >thin provisioned. But as I have tro create many VMs with 120Gb of disk >size >of which probably only a part during time will be allocated, it would >be >unfeasible to make them all preallocated. I learned that thin is not >good >for block based storage domains and heavy I/O, but I would hope that it >is >not the same with file based storage domains... >Thanks, >Gianluca
This is normal - gluster cannot allocate fast enough the needed shards (due to high IO), so the qemu pauses the VM until storage is available again . You can think about VDO (with deduplication ) as a PV for the Thin LVM and this way you can preallocate your VMs , while saving space (deduplication, zero-block elimination and even compression). Of course, VDO will reduce performance (unless you have battery-backed write cache and compression is disabled), but tbe benefits will be alot more. Another approach is to increase the shard size - so gluster will create fewer shards, but allocation on disk will be higher. Best Regards, Strahil Nikolov _______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/77DYUF7A5D6BIAYGVCBDKRBX2YWWJDJ4/
