Mailing List Archive

Hi all,

On 31.03.21 11:32, Michael Hierweck wrote:
> Hi all,
>
> with DRBD 9.0.25 we experience problem with the syncer rate.
>
> Using default settings our IO system gets overloaded, especially when multiple resources are be
> resynced in parallel.
>
> Neither
>
> drbdadm peer-device-options --c-plan-ahead=X --c-max-sync-rate=Y <res>
> drbdadm peer-device-options --c-plan-ahead=0 --resync-rate=Y <res>
>
> seem take any effect even when setting Y to very low values, such as 1M.

we ware able to slow down DRBD sync by applying:

drbdadm peer-device-options --c-plan-ahead=0 --resync-rate=100 <res>

(Yes, 100, not 100M.)

Syslog:

Resync done (total 1212 sec; paused 0 sec; 43256 K/sec)

I cannot explain how this setting fits with the result.

Thanks in advance,

Michael
_______________________________________________
Star us on GITHUB: https://github.com/LINBIT
drbd-user mailing list
drbd-user@lists.linbit.com
https://lists.linbit.com/mailman/listinfo/drbd-user

On 3/31/21 2:32 AM, Michael Hierweck wrote:
> Hi all,
>
> with DRBD 9.0.25 we experience problem with the syncer rate.
>
> Using default settings our IO system gets overloaded, especially when
> multiple resources are be resynced in parallel.

It's possible to configure "serialized resyncs" by setting the
"resync-after" disk option.

For example, to suspend r1's resync until r0 has completed it's resync,
you would set the following:

----
resource r1 {
disk {
resync-after r0;
}
...
}
----

>
> Neither
>
> drbdadm peer-device-options --c-plan-ahead=X --c-max-sync-rate=Y <res>

The setting to limit the maximum rate of resync is 'c-max-rate', not
'c-max-sync-rate'. Maybe that helps, or is just a typo in your email.

> drbdadm peer-device-options --c-plan-ahead=0 --resync-rate=Y <res>
<snip>
If I recall correcly, since DRBD 8.4.0 the 'resync-rate' is used as a
"starting point" for the dynamic resync controller, so I'm not sure
setting that will have a meaningful effect.

--
Matt Kereczman – Solutions Architect
+1 503 573-1262 x205
matt@linbit.com

LINBIT | Keeping the Digital World Running
DRBD – Corosync – Pacemaker

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
_______________________________________________
Star us on GITHUB: https://github.com/LINBIT
drbd-user mailing list
drbd-user@lists.linbit.com
https://lists.linbit.com/mailman/listinfo/drbd-user