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Xen virtual server problems, 'blocked for more than 120 seconds'

Linux Kernel, Network, and Services configuration.
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Netservicesgroup
Posts: 1
Joined: 2021-08-24 07:19

Xen virtual server problems, 'blocked for more than 120 seconds'

#1 Post by Netservicesgroup »

Hi, I'm hoping someone will have some advice.

We are in the process of migrating off of another distro onto Debian, and are running Debian 10 Xenproject hypervisors with paravirtualized Debian virtual servers,

The hypervisors are running kernel 4.19.0-11-amd64 #1 SMP Debian 4.19.146-1 (2020-09-17) x86_64 GNU/Linux.

The virtuals are 4.19.0-13-amd64 #1 SMP Debian 4.19.160-2 (2020-11-28) x86_64 GNU/Linux.

The virtuals operate normally for some period of time, sometimes measured in days and sometimes weeks. But eventually, some virtual will decide that it's time has come, and it will go unreachable over http, ssh, etc. They all do it now and then but never at the same time.

Nothing is written to the logs when it happens, but at the console of the broken virtual you see a page of error messages like this:

Code: Select all

INFO: task kworker/u2:1:52 blocked for more than 120 seconds.
     not tainted 4.19.0-14-amd64 #1 Debian 4.19.171.2
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
INFO: task mysqld:645 blocked for more than 120 seconds.
     not tainted 4.19.0-14-amd64 #1 Debian 4.19.171.2
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
From what I can tell, it's related to the virtual being unable to use its virtual disk, Also notable that the virtuals with heavier disk use seem to have the failure happen more frequently than the others.

The virtual disk image files are set up this way:

<driver name='qemu' type='raw'/>

Search engines are finding old references to a problem like this with Debian and Xen, but the references are for older versions of Debian, and there weren't any solutions to be found, there.

I'm out of ideas on what to try to make this stop happening. Does anyone have any insights?

Thanks!

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