[DRBD-user] Write performance 0.7.4 versus 0.7.5 on Primary + SyncTarget

Bernd Schubert bernd-schubert at web.de
Tue Oct 5 17:59:08 CEST 2004

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


On Tuesday 05 October 2004 17:13, Benoit.Ropartz at alcatel.fr wrote:
> Ok i have tested writes speed during normal operation and i got sames
> results
> with two versions ~ 600 Ko/s.
>
> But why i find difference when syncing is active (30ko=>2ko) ???

Just read the changelog of 0.7.5, the write speed barrier of 30MB/s has gone 
with this version. Probably you are now syncing with the full speed of your 
hardware (check the logs or /proc/drbd during the synchronisation to get the 
sync speed) and with the previous version only at 30MB/s and so there was l 
more capacity left for normal writing operation.

>
> And 2ko/s is very small....

Btw, what does the unit 'ko' mean? kilo operations?

>
> Your idea is fine (rate=5M) if there is only one resource synchronised but
> not if there are many.

Sorry, I don't understand what you mean. The syncer {} definition is per drbd 
group. Anyway, same hardware devices should be different sync groups, e.g. 

resource resource drbd0 {

...

        syncer {
                rate 5M;
                group 1;
        }
...

}

resource resource drbd1 {

...

        syncer {
                rate 5M;
                group 2;
        }
...

}


Cheers,
 Bernd



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