[DRBD-user] DRBD sync slow

Ben Timby btimby at gmail.com
Thu May 6 14:58:30 CEST 2010

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Cristian, I have two suggestions for you.

1. You could increase the syncer rate and see what happens. However,
it is possible that your disk throughput is slowing down the process.
DRBD syncs can be limited by both disk subsystem and network
subsystem.

http://www.drbd.org/users-guide/s-configure-syncer-rate.html

2. If your disks have sync'd in the past, they may contain many
identical blocks. The default syncer will sync them anyway. I was able
to speed up a sync by using a checksum algorithm. However, this is
basically a tradeoff of disk/CPU overhead for network I/O. In my case
network I/O was the scarcer resource, so the sync speed was helped
immensely. If your disks are slow or CPU is not up to the task, then
this could actually hurt your sync rate (or make no difference).

http://www.drbd.org/users-guide/s-configure-checksum-sync.html

On Wed, May 5, 2010 at 8:32 PM, Cristian Rojas <intipu at googlemail.com> wrote:
> Just looked at /proc/drbd and im getting:
>
> speed: 192 (320) K/sec
>
> but I have setup 30M on syncer rate in /etc/drbd.conf
>
> Any hints guys?
>
> Thanks



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