[DRBD-user] Initial Sync - Fast then really slow

Jeff Goris jeff.goris at whiterabbit.com.au
Tue Apr 6 07:18:24 CEST 2004


> So, I reset the sync, and I notice its going a decent clip in the 40meg
> range.  I distract myself and get to another chore.  I come back to the
> machine and notice this rate has dropped to about 500.  (It happens to
> do this not too far after reaching near the 10gig mark).  I knocked up
> the sync-min to 10megs.  However, this is still occurring and I'm not
> quite sure whats going on.
>
> I am running an IDE software raid on each box as well, which I know
> could have some impact on performance, although I'm guessing it should
> be capable of sustaining more throughput than just 500k/s.
>
I'm running a fairly similar configuration. RedHat 9.0, drbd-0.6.12, channel
bonded gigabit crossover, with 90GB software RAID devices on each node and I
came across this same problem when I set it up.

> Any idea's?  Thanks,
>
Perhaps check the clocks on each machine. I did notice that the clocks on
each of my hosts were different as one was set to the wrong timezone. I
fixed the timezone and had each host sync off an NTP source to ensure they
kept accurate time. Then the replication rate was stable the whole way
through at about 22,500 K/sec.

Jeff.




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