Hi, my approach:

Design your primary pool on fast disks with a size that is enough for your
daily backupvolume. 
If the daily backup volume is not to much and the main volume comes from
daily changing files you can size your primary pool
so that the files expire on primary before they migrate to the next pool.
A second pool on cheaper ATA disk is good enough for the files that (never)
change. 
A FastT with Raid 5 should be fast enough and can be mixed with fc and ata
disks.

Kind Regards
Stefan Holzwarth


> -----Ursprüngliche Nachricht-----
> Von: Miles Purdy [mailto:PURDYM AT FIPD.GC DOT CA]
> Gesendet: Montag, 2. Februar 2004 17:32
> An: ADSM-L AT VM.MARIST DOT EDU
> Betreff: Re: Primary storage pool on disk
> 
> 
> My $0.02...
> 
> GOOD storage doesn't get a whole lot cheaper than the FAStT.  
> Of course you can use ATA disks, but I wouldn't recommend it. 
> At 7TB, they have quite a bit of data. If they already have a 
> FAStT, but some drawers with 143GB disks. RAID 5 is fine for 
> this situation. If they want a cheaper solution, use tapes :).
> 
> Miles
> 
> 
> >>> stef.coene AT DOCUM DOT ORG 30-Jan-04 12:45:47 PM >>>
> Hi,
> 
> I have a customer who wants to put his primary storage pool 
> on disk.  This is
> now 3TB and can grown up to 7TB.  Incremental backup is appr 
> 300GB/night.
> 
> But I have some questions?
> - What kind of disks should I use?  (the customer has a FastT 
> from IBM with
> fiber disks, but he wants a cheaper solution)
> - What kind of raid level as protection?  Raid5, JBOD, Raild 
> 0+1, ... ??
> - Should I use a DISK type or FILE type storage pool?
> 
> Thx.
> 
> Stef
>