Re: databases and RAID ...

Peter Eisentraut <peter_e@gmx.net> writes:

> There are also other levels.  One poster talked about RAID 10 which
> appears to be a mirrored RAID 5.

Those are multi-level RAID systems:

- RAID (0+1) RAID 1 (high availability) plus RAID 0 (enhaced I/O
performace through striping).

- RAID (3+0) A logical volume with several RAID 3 logical member
drives.

-RAID (5+0) A logical volume with several RAID 3 logical member
drives.

-RAID (5+1) Requires multiple RAID controllers. Each layer-1 RAID
controller handles one RAID 5 logical drive and layer-2 RAID
controller performs RAID 1 (mirroring) function to the virtual disks
controlled by all of the layer-1 RAID controllers.

- RAID (5+5) Requires multiple RAID controllers. Each layer-1 RAID
controller handles one to several RAID 5 logical drives and layer-2
RAID controller performs RAID 5 to the virtual disks controlled by all
of the layer-1 RAID controllers.

- RAID 10 Logical volume with RAID 1 logical drives; stripping plus
mirroring.

- RAID 30 Logical volume with RAID 3 logical drives; RAID 3 plus
striping.

- RAID 50 Logical volume with RAID 5 logical drives; RAID 3 plus
striping.

All about RAID: "The RAID book" from the RAID Advisory Board.

Regards,
Manuel.