[DRBD-user] DRBD is deadly slow.

Stefan Seifert nine at detonation.org
Tue Mar 30 15:50:39 CEST 2010

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


> 2010/3/30 Balreddy Medipally <balreddy.m at imimobile.com>
> 
> > I am running DRBD 8.3.0 on RedHat Enterprise Linux AS 4.8 64-bit
> > OS for production purpose. MySQL works superfast in when load was not
> > there, when load was there it become deadly slow. Can any one please
> > help me to make it faster.

On Tuesday 30 March 2010 15:35:06 PN wrote:
> Try to increase the syncer rate to a much higher number and restart DRBD on
> both nodes will definitely help to increase the sync speed.

If the volumes are in sync the sync speed should not affect DRBD performance 
in any way. And if they are not in sync, raising sync speed would even make 
the performance worse, since DRBD would spend more resources on resync and 
less on the application's workload!

This sounds more like something for the DRBD performance tuning webinar. 
Tuning of al-extents, network parameters and the like. Also if a battery 
backed RAID controller is being used (and it should):
    no-disk-barrier;
    no-disk-flushes;
    no-md-flushes;
can be used which make a huge difference in writing performance. But in any 
case the webinar and some good benchmarking should be the first step.

Regards,
Stefan



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