[ILUG] Why RAID

[John Coleman]

On Fri, 16 Jul 2004 18:15:47 +0100, Gareth Eason <bigbro at skynet.ie> wrote:
> 
>        Hi,
> 
>     Since it's NOT a production environment, and cost is an issue, I
> would consider dropping the hot spare. If a drive does go, you'll fail
> over and lose resilience - but that should be enough to leep you going
> until you get a chance to acquire and install a new drive and rebuild
> your resilience.
> 

Yeah, I'm kinda leaning that way myself :)

>     I wouldn't dream of removing the hot-spare from a production system,
> or from a 'difficult to physically access' system (colo box or similar)
> - but with it running at home it's just eating into the MTBF of your
> hot-spare and providing a secondary layer of resilience which you'll
> probably never ever need to use. I'm sure you can think of a good use to
> put the money saved from that drive to ;-)
> 
>     RAID1 for the operating system might not be a bad idea. More than
> one person I know has been caught out because they 'forgot' that without
> their raid configuration they were unable to access their data, even
> though it was safely just sitting there in a fully operatinal RAID
> array... Moral: Make sure you have a couple of backups of your RAID
> drivers and your RAID configuration :-)

I've already discovered that pitfall myself, and I don't wish to go
through it again ;)

> 
>     Also, if you're building up your aray over time, RAID4 is
> expandable, RAID5 is not (AFAIK) without destroying the data and
> restriping across all the drives. ext3 with RAID4 fully supports dynamic
> addition of partitions to an array.
> 
>     Best regards,
>     -->Gar
> 

This is the card I'm looking at buyin:
http://www.lsilogic.com/products/serial_ata_raid/1506064.html
Under the "Features" blurb it says:
 FlexRAID®:
    -Online RAID level migration
    -Online capacity expansion

I am planning to use XFS for the array, which I believe is expandable...??

JohnC