what would RAID5 cost as a minimum?

[stevech]

I'm beginning to have enough GB of archived shows to worry about drive failure. I know that if these fit on a single, say, 250G drive, the cheapest backup is another like-sized drive and copy now and then.

But, today, for those of us not wanting to spend $$$ on HTPC,
what would a low cost RAID5 cost? Must the controller card be PCI?

[ke6guj]

it all depends

What do you want to spend, what features do you want. I have seen 2-port RAID 1 PCI cards for less than $100 IIRC. Do you need PCI?, if not, Raid cards pretty much are available in every slot configuration out there; ISA, PCI, PCI-X, PCIe.

With RAID 1, you lose 50% of your drive capacity, so dollar-for-dollar, it is the most expensive. With RAID 5, you lose 1 drive out of your entire array. IF you have 3 drives, data goes on 2. With 4, data goes on 3, etc. So, your expense in "lost" HD space goes down.

You can get Raid cards for SCSI, P-ATA, S-ATA drives. Some higher-end cards will even let you expand your array by adding drives (OCE- online capacity expansion) without losing your data. Normally, any change to the array meant tearing it down adn rebuilding from scratch, in the process, losing all data.


The card I have is the Adaptec 2810SA, it is an 8-port S-ata card with OCE. It ran about $400. I started with 3 HDs, and have expanded it to 5 without any problems. I am planning on popping in 2 more HDs for a total of 7-300GB HDs.

PCI and PCI-X cards and motherboards will usually intermix, but you will only run at PCI speeds. For our needs, that speed is usually just fine.

[gplasky]

As another option, for the cost of 3 drives and a gigabit NIC card I loaded FreeNAS on an old IBM P4 1.5GHz with 512MB of RAM. No cost for the PC. Sure it's doing software RAID 5 and people will say Hardware RAID 5 is better and faster and it probably is but you know what.....this box ain't doing anything else but storing files. So no overhead. So when I have the server client, 2-PC clients and an MVP watching recordings or rips from it-no stuttering. No hesitation. I'm extremely happy with it. And for the price (3 X 400GB drives at $200 each) You can't beat it.

Gerry

[jptaz]

I prefer Hardware RAID cards...but I agree with Gerry that if you have an old PC and the space for it then the solution FreeNAS is a pretty good route...also that mean you can put a bunch of cheap SATA cards in the box and expand more affordably.

I chose Hardware RAID for several reasons:
1. Physical Space...only room for one server in the closet and it had to be both SageTV Tuner Farm and Disk arrary

2. Didn't want the added noise of another PSU and case with drives and another box on 24 x7.

3. Wanted good enough performance during a rebuild of the RAID 5 and still be able to full function....though I am guessing even with software RAID FreenNAS can fo this with a Pentium 4 1.5 Ghz.

John

[stevech]

how many drives in a hardware controller based RAID5 system?
Or do most budget minded people who want backup just do mirroring?

(I use TruImage to do daily backups of the boot partition but that's just 20MB or so and 4GB once a week).

[jptaz]

The real question is what is your goal for RAID?

Are you protecting a boot drive failure from bringing down your system and a small set of data?

Are you protecting your video storage?

The minimum number of drives required by RAID 5 is 3 drives( Software or Hardware)....and your capacity is 2 x the smallest drive size with 3 drives in the RAID. The problem with doing the minimum is that at 3 drives most RAID 5 systems are slower than a single drive system because of the overhead and I personally think that performance is not worth the investment unless you have at least 5 drives in RAID 5, but you could certainly get a card with OCE and start with 3 drives and add more later....I basically did this with my setup since I only have 8 drives and can add 4 more later.

So the short answer is that yes if you are budget minded and do not want to protect large quantities of data go with a mirrored boot drive and accept the risk of a video drive failing or accept the adding expense of needing 2 times the numbers of video drives.

If you are budget minded and really want to protect alll your drives go with a software based RAID solution like FreeNAS mentioned before.

John