[ardour-users] Ardour DAW - Hardware advice please..

[Doug McLain]

Joe Hartley wrote:
> On Wed, 15 Dec 2004 12:33:36 +0100
> "Happyface" <happyface at happyface.dk> wrote:
> 
> 
>>2. Would I gain much performance in using some kind of RAID system for the harddrives ?
> 
> 
> This is the only part of this I can really comment on:  no, you won't
> get any performance boost from a RAID.  RAIDs help protect data, but
> cannot write it any faster than with a single drive, and in some cases
> a RAID will slow you down because it'll spread the data across multiple
> drives, and there's overhead involved in doing so.
> 
> To protect my sessions, I have a process to rsync my /tape directory off
> to my server at 4:00 AM nightly.  That's saved me at least once!
> 
This is inaccurate.  You describe RAID 1, which is strictly mirroring. 
It requires an even numder of disks, and the available space is the 
(size of the smallest disk * N) / 2 (N = number of disks).  Note you 
shoudl always use equal size disks, though.

RAID 0 for instance is the opposite, it uses striping, and is strictly 
used for performance and space.  In this scenario there is no redundancy 
at all, and the avialable space become s * N.  Performance is increased 
by doing parrellel xfers to the drives.  Not only is there no 
redundancy, RAID 1 is actually less safe for data storage then a single 
drive, since if 1 drive fails all the data is lost.  Obviously, the more 
drives in a RAID 1 array, the higher the chances for loss of data.

The list goes on and on, but I think its safe to say RAID 5 seems to be 
the popular choice for home useres.  It distributes parity info across 
every other disk in the array besides the one that the current chunk of 
data is going to. In the event of a disk failure, the dead drive it 
replaced and data rebuilt to it by the controller from the parity info 
gathered from all the other drives in the array.  The avail space 
equates to (s * N) - 1. For example, I just built a RAID 5 array using 5 
(no correlation) 250GB drives, which  provides 1TB of space with 
excellent performance.

Doug
-- 
http://nostar.isa-geek.com/