[mythtv-users] RAID 1 - friend or foe?

[Richard Dale]

>> Would using two modern SCSI hard drives, hanging off an Adaptec 
>> controller, in a RAID-1 configuration, help or hinder video 
>> recording/playback, versus using a single disk only.

> Hardware RAID one should incur no or very very little performance hit on 
> writes since data is written to both disks simultaneously and could 
> improve read performance by reading sectors from either disk as needed.

The RAID-1 controllers that I have seen only appear to read from a single
disk.  Only when they are in a striping RAID mode (eg. RAID 0, RAID 5 or
RAID 10) do they read from multiple disks.

So, in answer to the question, they do nothing for recording or playback
performance except in cases where you have a disk failure where it helps
tremendously :-)

On a database server I run 8x15K RPM drives with a MegaRAID SCSI 320-2X
controller in RAID 10 (ie 4 stripes, each stripe mirrored).  Only 4 of the 8
drives "flash their lights" when doing a big read.

Cheers,
Richard.