[SOLVED] Re: storagedriver domain limited to 61 "shares" - Xen 4.16.6 pre2

["J. Roeleveld" <joost@xxxxxxxxxxxx>]

On Monday, February 12, 2024 10:43:56 AM CET Juergen Gross wrote:
> On 12.02.24 10:22, J. Roeleveld wrote:
> 
> > On Monday, February 12, 2024 7:40:39 AM CET Juergen Gross wrote:
> > 
> >> On 11.02.24 17:21, J. Roeleveld wrote:
> >>
> >>
> >>

> >>
> >> My first guess would be that the driver domain is limited by the max
> >> number of Xenstore nodes it is allowed to own.
> >>
> >>
> >>
> >> You can raise the default of 1000 nodes per domain (how to do that
> >> depends on the Xenstore type you are running, xenstored or oxenstored).
> > 
> > 
> > Hi Juergen,
> > 
> > I just tested with -E set to 15000 (15k) but am still seeing the same
> > issue.
 
> > On the storagedomain, I see the following in dmesg:
> > ===
> > [58855.383841] vbd vbd-16-51729: 7 adding watch on
> > /local/domain/16/device/vbd/51729/state
> > [58855.384545] vbd vbd-16-51729: xenbus: watch_otherend on backend/vbd/
> > 16/51729 failed.
> > [58855.384548] vbd: probe of vbd-16-51729 failed with error -7
> > ===
> > 
> > followed by several like:
> > ===
> > [58855.407134] vbd vbd-16-51730: 7 adding watch on backend/vbd/16/51730/
> > physical-device
> > [58855.408205] xen-blkback: xen_blkbk_probe failed
> > [58855.408242] vbd vbd-16-51730: 7 xenbus_dev_probe on
> > backend/vbd/16/51730
> > [58855.408405] vbd: probe of vbd-16-51730 failed
> > with error -7
> > ===
> > 
> > The part "adding watch" makes me wonder about the option:
> > -W, --watch-nb <nb>     limit the number of watches per domain,
> > 
> > 
> >>From the code, I find the default is 128. Is there any way to find out how
> >>many 
>>
> > are currently set on my system and what a good amount would be?
> 
> 
> Oh, the relevant pieces have been backported due to several XSAs for
> Xenstore.
> 
> You should be able to issue:
> 
> xenstore-control quota
> 
> For showing the current settings and
> 
> xenstore-control quota set watches 256
> 
> for changing the current quota value for watches. Same should work for
> other quota.
> 
> xenstore-control quota <domid>
> shows the current number of used up resources of a specific domain.

# xenstore-control quota 2
Domain 2:
nodes           :     1947
watches         :      127 <----
transactions    :        0
outstanding     :        0
memory          :   213363

Ok, this definitely shows I'm basically at the limit :)

> > I am considering trying 256 for this.
> > Is there anything I need to be aware off before making this change?
> 
> Using above commands: no.

Thanks.

And after setting this to 256, I can now add the new VM to my system.
Thank you very much for all your assistance.

--
Joost