[ale] RAID, IDE and/or Linux

[Jeff Hubbs]

>
> If you are going IDE, and wanted the max in safety, I would suggest 
> using TWO pci-ide controllers (non-RAID, or RAID0/striping), and use 
> software RAID1/mirroring across them.  That way you can protect 
> yourself and have any easy replacement in the case of a controller 
> failure.
>
> I've not seen seen any setups of "3 equal drives" in Linux (I have in 
> HP-UX), but IIRC from reading the md-config docs it doesn't seem to 
> support more than 2 disks for mirroring.
> another note:
> http://unthought.net/Software-RAID.HOWTO/
> 3.2 Hot Swap
> This has been a hot topic on the linux-kernel list for some time. 
> Although hot swapping of drives is supported to some extent, it is 
> still not something one can do easily.
> Hot-swapping IDE drives
> Don't ! IDE doesn't handle hot swapping at all.....
>
This is true - mirroring across drives on separate controllers is a way 
to absorb a controller failure.  I know of no straight mirror 
implementation that utilizes more than two drives/partitions.  

IDE doesn't contraindicate hot-awapping out of hand (witness the awesome 
Raidzone rigs by Consensys), but your mobo and PCI-card IDE controllers 
won't handle it.  

Dave, in my case, I need the capacity more than I need instant fault 
tolerance, so my file server doesn't use RAID but it does have a Travan 
TR-5 tape drive.  The 20GB drive that I keep CD contents on but the 
other drive - 80GB - has an on-partition backup (to help with accidental 
deletions) and gets backed up to tape.  It's best if the tape is taken 
away from the server so that the fire that destroys the server doesn't 
also destroy the tape.

BTW, Dave, I put both the drives in drive coolers so that they run very 
cool.  They SHOULD last a good long time.


- Jeff


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