RAID5 for Linux

[mark at buttery.org (Mark J. Dulcey)]

Rich Braun wrote:

> - The stated requirements of serial ATA and hot-swap imply high-end hardware
> that will come at a hefty price.  I'm frugal, personally, and generally
> question whether high-priced features really fit the bill.  For example,
> hot-swap can be justified on a mail server at an ISP but not at most 9-to-5
> corporate sites where it's easy enough to shut the system off for 5 minutes at
> the end of the workday.  Serial ATA can be justified if you need 15,000rpm
> drives because the system is handling 1000 transactions per second in a
> banking app, but not if you're running a Clearcase server for a half-dozen VB
> programmers.

The price penalty for Serial ATA is pretty small now; you might pay an 
extra $25-$50 for a motherboard that has it, and $0-$50 extra per drive, 
and those numbers will only drop with time. (I wouldn't be surprised if 
Serial ATA drives are CHEAPER than their parallel ATA equivalents a year 
from now, just as DDR SDRAM is now less expensive than the older non-DDR 
memory.) Unless your budget is REALLY tight, there is little reason not 
to use it in a new system. True, you can't get really low-end, low 
capacity drives in Serial ATA, but you're probably not going to put 
those in a server anyway.

Serial ATA gets you smaller, easier to route cables, and the potential 
for hot-swapping. In theory, even with a basic system using 
motherboard-based Serial ATA, you could open up the case and swap out a 
Serial ATA drive. The drives support it (you can pull the data and power 
connectors without damaging them), but the controllers built into 
motherboards and the OS may not. If you want to try that approach on the 
cheap, choose a case where the drives mount with rails and face out. 
Many recent Antec cases do that, including the super-quiet Sonata.

High-end Serial ATA drives (10,000 RPM and up) are expensive. But 
high-end drives are always expensive, no matter what interface they have.