[DRBD-user] sync very slow

Leroy van Logchem leroy.vanlogchem at wldelft.nl
Wed Jan 3 13:41:07 CET 2007

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

>>> I've started drbd on both PC and the sync is running but the rate is
>>> 400K (in the configuration file I've a max rate=600M) and I must wait
>>> 7 day to end.
>> The 600M is unachievable with Gig-E. Maybe the value is too large, try
>> rate=99M and 'drbdadm adjust all'.
> I've tried rate=100M but is the same; the transfer rate is about 2MB/s
> and not  400KB/s  like  during sync phase, I think 400KB/s isn't correct.
> I've another  question:
> PC client with 100Mb network interface copy  a file to drbd partition (
> the rate is about 20Mb/s);is the rate of the 2 server linked with 2 1Gb
> network interface the same or not?
In short the drbd link should handle +/- 99MB/s. And your PC +/- 10MB/s.
> (is possible to have the sync rate > the copy rate?) 
Sure, but the problem is not your 'rate=' setting. Perhaps you first 
verify your
raw tcp speed using iperf*. You should get >925Mbit/sec over your cross-
cable. I have no clue about the slow transfer rate, any takers?

* http://dast.nlanr.net/Projects/Iperf2.0/iperf-2.0.2.tar.gz

PS: Please don't top-post

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