Raid Card controller for FC System

[Bill Davidsen]

Joe Tseng wrote:
> I saw a few people respond with saying how hardware RAID is overkill for 
> home use.  I had the system drive in my RH9 RAID1 file server at home 
> die on me last year; although I got a new drive and FC6 recognised the 
> RAID immediately I'm not sure whether my recovery was due to software 
> resilency or dumb luck.  I'm currently working on gathering parts for a 
> RAID5 file server as a replacement.
> 
> 1) If a RAIDed drive dies in a soft RAID setup can I assume I can't do a 
> hotswap?

Assume that you can if you have hot swap enclosures. Assume you will 
have to type a few commands as you do it, but it's relatively simple to 
follow the steps. Assume that if you have configured with a spare drive, 
SW raid will use it fairly quickly.

> 2) If my system drive dies again would a new system recognize my RAID5 
> array?

Yes, but the whole concept of a system drive is just wrong. You should 
be saying "a drive in my system array" and assuming the system stays up 
(if you have raid swap as well).

> 3) Does soft RAID5 compare favorably against hware RAID5?

yes, and performance enhancements are in testing now which will make it 
"more better" in the future.

More on HW vs. SW RAID:

A redundant system (I'm on one) has at least three drives. The boot 
sector is mirrored (raid1) over a small partition (200-500MB) on each, 
to allow something as dumb as the typical BIOS to boot in case of 
failure. The swap is raid10 (far two) for top swap-in performance, and 
so that my system doesn't crash in case of an error. The "system" can be 
any redundant array type, pick one for performance. Your application 
storage can be included with the system, or another raid type depending 
on your need for speed vs. reliability vs. cost.

With software raid you can have several types of raid on the same drives 
using partitions, and it works. Hardware controllers don't let you 
choose the proper type in units of anything smaller than a drive.

For a general desktop you can just make root, home, and any application 
one big old array, and only have the boot and swap broken out.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot