[DRBD-user] DRBD deadly slow

Felix Zachlod fz at sis-gmbh.info
Thu Nov 13 17:02:59 CET 2008

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

Hello and thank you for your Answer!

> -----Ursprüngliche Nachricht-----
> Von: drbd-user-bounces at lists.linbit.com [mailto:drbd-user-
> bounces at lists.linbit.com] Im Auftrag von Stefan Seifert
> Gesendet: Donnerstag, 13. November 2008 16:48
> An: drbd-user at lists.linbit.com
> Betreff: Re: [DRBD-user] DRBD deadly slow
> Just a wild guess: where do you store your drbd meta data? AFAIK RAID 5
> is no
> good option for meta data due to it's write latency. I'd guess that for
> 6 this is even more so.

The meta data is stored on a separate Partition on the same RAID-60 volume.
To test this with a raid-1 configuration I would have to screw up all
contents of the servers and waste 1TB netto capacity for drbd meta data.
That means I am nearly at a point where I would equal netto capacity of the
systems configured in raid 10, but I might try that if everything else
fails. But as far as I can see with iostat there is nearly no acivity on the
meta partition (or lets say very very little) so that I can't really believe
this to be the point- and of course- meta data write process is covered by
the raid controller's write cache too...

regards, Felix

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