Epia 5000 ITX board powerful enough for software RAID 5?
 

Not sure if this is a software or hardware question, so apologies in advance. The limitation is imposed by hardware so ......

I need a hand deciding whether I can pull off software RAID with my current ITX fileserver or not, I'm running out of room and need more space, with some redundancy.

I know the board should handle software RAID 1 (2x 400GB seagates), but I don't know if it could hand RAID 5 with 4 drives? (3 used, 1 hot spare). Is there any sort of "x number of drives = X amount of CPU grunt + safety margin" formula for software RAID or is it more arbitary than that? I'll be connecting the drives via a pci controller card to circumvent lba restrictions.

Server specs:
Via Epia 5000 - 533mhz / 512MB ram / 80GB hd, running Debian Woody.
Currently provides Apache, mp3 streaming / local play (ampache), MySQL, fileserving via NFS / HTTP, OpenSSH and HTDig (searching docs) to a maximum of 3 users.

Oh yeah and
<possible religious war>
Apart from tidier cabling, better air-flow and future-proofing, are SATA disks worth it? Last time I checked the jury was still out on whether SATA under Linux gave significant benefits.
</possible religious war>

Cheers

Pete

it's not the CPU so much as the power supply... that's a lot of heavy power users there. most itx boards recommend the use of smaller 2.5inch drives to make them manageable. how much power are you pulling into it? afaik the max the epia 5000 can take is about 100W? my epia 800 runs great on 55W but then it is totally diskless...

The board has a 220w power supply. I'm not sure how much of that it can make use of though.

According to http://resources.mini-box.com/online...simulator.html , I should be pulling just under 45 watts with two 3.5" drives and a 2x20 LCD to display mp3 tracks, going up to just under 70w with 4 3.5" drives, so whether the board can use 100w or 220w, I have at least a 30w safety margin minus whatever the sata card draws.

Unhelpfully, mini-box doesn't say whether they take into account the initial power draw on boot - I'll assume they don't. A quick look through via's website doesn't elicit useful info, so I'll have to go and rtfm when I get home to see how much juice it can use.

I can't afford laptop drives and if I ebayed for some old ones, I'd need loads to get comparable disk space.

I was (perhaps wrongly) under the impression that the CPU had to have a certain amount of grunt for stuff like building / rebuilding / maintaining the array - I take it you assume 533Mhz should be enough for a 3-person fileserver?

Cheers

Pete