[DRBD-user] DRBD performance

Laurent CARON lcaron at unix-scripts.info
Fri Oct 19 12:12:24 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.


Leroy van Logchem wrote:
> 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

Hi,


On the replicated disk

time dd if=/dev/zero of=/drbddisk/tmp bs=1M count=4000 ; time sync
4000+0 enregistrements lus
4000+0 enregistrements écrits
4194304000 octets (4,2 GB) copiés, 163,287 seconde, 25,7 MB/s
dd if=/dev/zero of=/drbddisk/tmp bs=1M count=4000  0.00s user 10.16s
system 6% cpu 2:43.29 total
sync  0.00s user 0.00s system 0% cpu 0.298 total


On the local disk

time dd if=/dev/zero of=/localdisk/tmp bs=1M count=4000 ; time sync
4000+0 enregistrements lus
4000+0 enregistrements écrits
4194304000 octets (4,2 GB) copiés, 87,4665 seconde, 48,0 MB/s
dd if=/dev/zero of=/localdisk/tmp bs=1M count=4000  0.00s user 7.42s
system 8% cpu 1:27.47 total
sync  0.00s user 0.00s system 0% cpu 2.782 total

> You might want to try: al-extents 3833;

I'm gonna try this.

> Does your network reach 100MB/s? Verify with iperf or netpipe.
> 
> 

Performance of the network ain't bad:

123: 8388611 bytes      3 times -->    896.07 Mbps in   71423.18 usec



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