[DRBD-user] mount seconday read-write

H.D. devnull at deleted.on.request
Thu Jun 28 21:58:36 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.

Lars Ellenberg wrote:
> whether or not this is noticable depends very much on the actual
> workload, and on the lower level io subsystem.

Right, but you always have to do backups and backups always cost
performance. I think one should plan systems with that in mind and
enough headroom from the beginning.

As the secondary box is usually less loaded than the primary, I prefer
to do it there.

We run PostgreSQL under heavy OLTP load and drop back from ~1500  to
~1150 TPS (test case, pgbench) during the secondary creating backup. So
yes, there sure is a big performance penalty, but as we have more than
enough headroom left, I have not bothered yet to move the snaps to
another PV.

Best regards,

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