Re: Fwd: Multiple disks: RAID 5 or PG Cluster - Mailing list pgsql-performance

From Greg Stark
Subject Re: Fwd: Multiple disks: RAID 5 or PG Cluster
Date
Msg-id 8764wa3n9t.fsf@stark.xeocode.com
Whole thread Raw
In response to Re: Fwd: Multiple disks: RAID 5 or PG Cluster  (Michael Stone <mstone+postgres@mathom.us>)
List pgsql-performance
Michael Stone <mstone+postgres@mathom.us> writes:

> it is possible to have a mirror of more than two disks (which would have the
> same read advantage as the striped configuration with the same number of
> disks) but this is rarely seen because it is expensive.

Actually three-way mirrors are quite common for backup purposes. To take a
backup you break the mirror by taking one of the three copies out. Back it up
at your leisure, then just resync it in time for the next backup.

--
greg

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