[DRBD-user] drbd syncing all resources hangs business app

[Roland Kammerer]

On Fri, Sep 15, 2023 at 09:53:44AM +0200, Ferran Alchimia wrote:
> We have 39 defined resoruces using the same settings. And all these
> resources are running on the same RAID supported by two physical nvme ssd
> drives.
> We have two combined hosts and a diskless satellite host. The network card
> between the two hosts is a 1Gb card.
> 
> I have read the following guide
> https://kb.linbit.com/tuning-drbds-resync-controller and I think our
> current installation might have to be tuned in order to avoid those
> application hungs.

yes, obviously it is a good idea to check these settings, some defaults
are a bit outdated for modern systems.

In general there is also a "resync-after" setting where you can build a
"resync chain" of resources, so that not all resources start syncing at
the same time, but after each other in the defined order.

Your setup looks like a Proxmox setup so you use LINSTOR, and it has a
"DrbdOptions/auto-resync-after-disable" option. You might want to try if
that helps and is good enough for you. disclaimer: I know it was enabled
by default in a release and pulled back afterwards, but things might
have improved enough, at least in such medium sized scenarios.

Regards, rck