Promise FastTrak 100 onboard ATA RAID controller

Jason Gurtz jason at
Wed Jul 2 08:45:52 PDT 2003

Alexander E. Patrakov wrote:

> Variant 1: Don't use it at all. Use "md" software RAID on main IDE interfaces 
> (they are ATA133, but there is also a not-so-often-used CD-RW attached to one 
> of them), as we do now.

If the hardware raid works, no way I would even consider a software raid.

> Variant 2: Move the disks to the Promise controller (ATA100, but no CD-RW), 
> use the same "md" software RAID.

2 striped disks would have trouble overwhelming a 100MB/s interface, let
alone a 133 MB/s one.  Since you're (smartly) doing mirroring there is
no gain at all to having a 133 bus instead of 100.  I would put the
CD/RW seperately from the disk bus('s) in any case, that is important.

> Variant 3: Move the disks to the Promise controller and use the pdcraid driver 
> (it has version 0.03 beta, I am not sure that it is stable enough).

Nothing to do by try it out...  This would be the recomended setup if
the driver works.

> Another couple of questions: How do I know if one of the mirrored hard drives 
> fail, for each variant? Can I replace a disk with a disk of higher volume in 
> the case of failure?

Can't speak for the sw raid but for hw raid it depends on the
driver/controler.  Even in the scsi raid arena there are cheap
controlers that can not do capacity expansion.  You can usualy always
substitute a larger drive, but in many cases the extra capacity won't be
used.  It's also generaly a bad practice to mirror 2 different
size/brand/speed drives.




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