[DRBD-user] drbd is performing at 12 MB/sec on recent hardware

Bart Coninckx bart.coninckx at telenet.be
Tue Oct 14 18:32:50 CEST 2008

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

Hi all,

I previously posted about a sync going somewhat slow (managed to get it up to 
I figured this could be just the syncing, so I decided to do some performance 
tests as mentionned in the webinar.

I used: 
dd if=/dev/zero of=/dev/drbd0 bs=1G count=1 oflag=direct

and the output was:

1073741824 bytes (1.1 GB) copied, 86.4031 seconds, 12.4 MB/s

Not very exciting. 

The server is a HP ML370 G5 with a 1TB RAID-5 setup. The controller used the 
cciss driver. DRBD is 0.7.22. OS is SLES 10 SP1. The network link is gigabit, 
full duplex, set to 1000 Mbit. 

I plan to enable write back cache, but I wonder if that is going to make THE 

What else could I do to boost this? Use another I/O scheduler?

Thank you,


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