[ovirt-users] Re: ImageIO Performance
On Thu, Feb 9, 2023 at 7:03 PM Nir Soffer wrote:
>
> On Mon, Feb 6, 2023 at 10:00 AM Jean-Louis Dupond via Users
> wrote:
> >
> > Hi All,
> >
> > We backup our VM's with a custom script based on the
> > https://github.com/oVirt/python-ovirt-engine-sdk4/blob/main/examples/backup_vm.py
> > example.
> > This works fine, but we start to see scaling issues.
> >
> > On VM's where there are a lot of dirty blocks,
>
> We need to see the list of extents returned by the server.
>
> The easiest way would be to enable debug logs - it will be even slower,
> but we will see these logs showing all extents:
>
> log.debug("Copying %s", ext)
> log.debug("Zeroing %s", ext)
> log.debug("Skipping %s", ext)
>
> It will also show other info that can help to understand why it is slow.
>
> > the transfer goes really
> > slow (sometimes only 20MiB/sec).
>
> Seems much slower than expected
>
> > At the same time we see that ovirt-imageio process sometimes uses 100%
> > CPU
>
> This is possible, it shows that you do a lot of requests.
>
> > (its single threaded?).
>
> It uses thread per connection model. When used with backup_vm.py or other
> examples using the ovirt_imageio.client it usually use 4 connections
> per transfer
> so there will be 4 threads on the server size serving the data.
>
> Please share debug log of a slow backup, and info about the backup image
> storage
> for example, is this local file system or NFS?
I opened https://github.com/oVirt/ovirt-imageio/issues/175 to make
debugging such
issue easier.
Nir
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[ovirt-users] Re: ImageIO Performance
On Thu, Feb 9, 2023 at 7:03 PM Nir Soffer wrote: > > On Mon, Feb 6, 2023 at 10:00 AM Jean-Louis Dupond via Users > wrote: > The easiest way would be to enable debug logs - it will be even slower, > but we will see these logs showing all extents: Using the --debug option Run backup_vm.py with --help to see all options. ___ 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/HPJVPFQD32Q55ZALOLK6AQ6PFXNGLGMX/
[ovirt-users] Re: ImageIO Performance
On Mon, Feb 6, 2023 at 10:00 AM Jean-Louis Dupond via Users
wrote:
>
> Hi All,
>
> We backup our VM's with a custom script based on the
> https://github.com/oVirt/python-ovirt-engine-sdk4/blob/main/examples/backup_vm.py
> example.
> This works fine, but we start to see scaling issues.
>
> On VM's where there are a lot of dirty blocks,
We need to see the list of extents returned by the server.
The easiest way would be to enable debug logs - it will be even slower,
but we will see these logs showing all extents:
log.debug("Copying %s", ext)
log.debug("Zeroing %s", ext)
log.debug("Skipping %s", ext)
It will also show other info that can help to understand why it is slow.
> the transfer goes really
> slow (sometimes only 20MiB/sec).
Seems much slower than expected
> At the same time we see that ovirt-imageio process sometimes uses 100%
> CPU
This is possible, it shows that you do a lot of requests.
> (its single threaded?).
It uses thread per connection model. When used with backup_vm.py or other
examples using the ovirt_imageio.client it usually use 4 connections
per transfer
so there will be 4 threads on the server size serving the data.
Please share debug log of a slow backup, and info about the backup image storage
for example, is this local file system or NFS?
Nir
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