[NTLUG:Discuss] looking for raid & controller advice

[Kevin Brannen]

I need to build a file server for my church.  Rudundancy is a must, 
since I've lost several drives in the recent past (I'm not too keen on 
the WD2000 right now--I might even have some used ones to sell soon).  
I'm thinking a cheap way to solve this (as opposed to buying a NAS 
solution) is to get a semi-low cost computer, add 1G of RAM for lots of 
cache, and stick a 3ware 7506-4LP in it with 3 250G EIDE drives in a 
RAID-5 config, running Linux and serving the files out the Gb network 
port with a Samba server.  (Yes, the 2 clients are Win2k, ugh!)  So far 
so good.  I can get all the parts new, including a spare 4th drive for 
$1500, maybe somewhat less.

However, not ever having used any of the 3ware products with Linux, I've 
got a few questions:

* How big is the onboard cache?  Can't find that on the website.
* It advertises Linux support, and software called Disk Manager.  Does 
DM work under Linux?  Is it useful?  Or do you just tell the card via a 
BIOS like tool to go RAID-5 and the card handles it all automatically 
and Linux sees the card as 1 big drive.
* Will this card demand to be the "first drive"?  I've got an extra PCI 
EIDE card in my home computer that insists on being hda-hdd.  I could 
live with this but would prefer the MB drive be hda, and these drives be 
hde-hdh.
* It advertises hot-swap (ain't gonna do it!) and hot-spare.  How does 
it tell you when it has lost a drive?  Something in /var/log/messages or 
at next boot up?  Or something in /proc/whatever that needs to be 
monitored?  An annoying audible alarm would work, the Promise card says 
it has that.
* If in the future I want to add 1 more disk because I have room on the 
controller, will the card naturally just "expand"?  (if i have to tell 
it in some setup tool, that's OK)  Or will I have to save everything 
off, rebuild the whole array, then restore the data?  If the latter, 
then maybe I need to add the 4th drive in up front. :-)
* On single drive systems, I like to use a journaling file system (I 
prefer ReiserFS on Suse and ext3 on RH).  For RAID-5, does a journaling 
FS matter?  Or because of the redundancy will the faster but potentially 
less reliable ext2 do just fine?  (Note, the system *will* be on a UPS, 
so any outage < 5min probably won't even be noticed.)

For those that have read this far.  Has anyone used a Promise TX4000?  
It's *half* the price of the 3ware one, advertises a XOR engine and 
resizing capability (for adding that 4th drive to give me a 750G 
device).  Since the 3ware is about $240 and the Promise is about $110, 
the difference is almost the cost of my spare drive.  Is there any 
reason I should not go for the Promise card?  (looking for good & bad 
experiences)

Linux also gives me the option of using Software RAID, but that will 
require a 4-channel EIDE card because of the number of drives I want to 
use.  Does anyone know if the Promise TX4000 will support a non-RAID 
config; i.e. just be an EIDE controller and not impose HW-RAID on me?  
(please don't tell me how bad Software RAID is, I'm not trying to start 
a big discussion about that, but this is an option I must give due 
deligence to)

Thanks!
Kevin