[DRBD-user] unable to resync devices

Arne Altrichter arne at meteo-graphics.de
Sat Jan 19 16:30:54 CET 2008

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


we have 2 systems with DRBD. The DRBD sync is not active at the moment, 
because we are not able to resync the devices again. There is heavy 
traffic on the master via samba and nfs. The slave has about 350G data 
left to sync.
If we activate the DRBD daemon on the slave and the traffic on the 
master grows too much, the file system on the master will not response 
anymore. A simple "ls" lasts 30+ seconds. About 1 minute later 
everything is normal again. Within these minute the DRBD sync speed is 
normal or even rises to 10-20Mb/s.
The syncer rate is set to 5MB/s, but lowering it to 500kb/s does not 
make any difference.
First we thought it’s a problem with our raid controllers 
(http://forums.storagereview.net/index.php?showtopic=25923 and 
http://community.novacaster.com/showarticle.pl?id=7395&n=8001), but the 
sync speed should also be zero or at least very low while these gaps, 
but it is not.
The situation is completely reproducible. Certain jobs produces these 
gaps every time they run.

specs (identical systems):
- Xeon 3,0 Ghz
- Memory 2GB
- 3ware 9500
	- 1x Raid 5 with 5x250G
	- 1x Raid 5 with 5x500G
- 1gb cross over connection
- Debian Etch, 2.6.18-4-amd64
- version: 0.7.21 (api:79/proto:74)


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