[ovirt-users] Re: Q: Hybrid GlusterFS / local storage setup?
On Thu, Oct 15, 2020 at 8:45 AM Gilboa Davara <gilboad(a)gmail.com> wrote:
Hello Nir,
Thanks for the prompt answer.
On Wed, Oct 14, 2020 at 1:02 PM Nir Soffer <nsoffer(a)redhat.com> wrote:
>
>
> GlusterFS?
Yep, GlusterFS. Sorry, wrong abbreviation on my end..
>
>
>
> This will not be fast as local device passed-through to the vm
>
> It will also be problematic, since all hosts will mount, monitor, and maintain leases
on this NFS storage, since it is considered as shared storage.
> If another host fail to access this NFS storage the other host will be deactivated
and all the VMs will migrate to other hosts. This migration storm can cause lot of
trouble.
> In the worst case, in no other host can access this NFS storage all other hosts will
be deactivated.
>
> This is same as NFS (internally this is the same code). It will work only if you can
mount the same device/export on all hosts. This is even worse than NFS.
OK. Understood. No NFS / POSIXFS storage than.
>
>
>>
>> A. Am I barking at the wrong tree here? Is this setup even possible?
>
>
> This is possible using host device.
> You can attach a host device to a VM. This will pin the VM to the host, and give best
performance.
> It may not be flexible enough since you need to attach entire device. Maybe it can
work with LVM logical volumes.
I've got room to spare.
Any documentation on how to achieve this (or some pointers where to look)?
It should be documented in ovirt.org, and in RHV documentation:
https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.4/...
I couldn't find LVM / block device under host devices / storage
domain / etc and Google search returned irrelevant results.
I tested locally, LVM devices are not available in:
Compute > Hosts > {hostname} > Host Devices
Looks like libvirt does not support device mapper devices. You can try:
# virsh -r nodedev-list
To see supported devices. The list seems to match what oVirt displays
in the Host Devices tab.
So you only option it to attach the entire local device to the VM, either using
pci passthrough or as a scsi disk.
Nir
- Gilboa
>
> Nir
>
>> B. If it is even possible, any documentation / pointers on setting up
>> per-host private storage?
>>
>> I should mention that these workstations are quite beefy (64-128GB
>> RAM, large MDRAID, SSD, etc) so I can spare memory / storage space (I
>> can even split the local storage and GFS to different arrays).
>>
>> - Gilboa
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