[DRBD-user] DRBD performance

Leroy van Logchem leroy.vanlogchem at wldelft.nl
Thu Oct 18 10:02:17 CEST 2007

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

> Performance over the DRBD partition:
> $ dd if=/dev/zero of=./tmp bs=4096 count=1000000
> 1000000+0 enregistrements lus
> 1000000+0 enregistrements écrits
> 4096000000 octets (4,1 GB) copiés, 84,7843 seconde, 48,3 MB/s
> Do you guys have any idea of the bottleneck of that setup ?

The numbers you get don't include the sync, you want to know when it's 
*on* disk too.
time dd if=/dev/zero of=./tmp bs=1M count=4000 ; time sync
Imagine a server with 64GB of memory..the cache effect would be quite large.
You might want to try: al-extents 3833;
Does your network reach 100MB/s? Verify with iperf or netpipe.


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