Help with RAID 5 controllers.

[drumma_boy]

Hey, i've been searching the internet now for 2 days and i can't seem to find what i need.

I'm running an old AMD athlon 1800+ as a small server at my house, and i want to run RAID 5 on it.

Now, the motherboard doesn't have PCI-X on it, so I'm needing a PCI controller card, but it also has to be hardware RAID because the CPU won't handle that and everything else.

Is there a 4-port SATA 300 hardware RAID 5 PCI controller anywhere?!?

The closest i've found is this:

PROMISE FastTrak TX4310 Serial ATA-300 PCI RAID Controller, Quad Channel.

But that's apparently basically just a software controller.

Any help would be much appreciated...

Thanks,

Paul

 

[Madwand]

Most if not all PCI-X RAID controllers should be backwards-compatible with PCI. If you limit the search to pure PCI controllers, you'll probably be restricted to older or poorer cards. There should be greater economies of scale with PCI-X cards.

Some Athlon XP chipsets aren't noted for their PCI bus performance, so it's probably best to forget about spending a small fortune on a "pure hardware" RAID controller -- you'll be limited by the PCI bus in even the best case, often more so with an Athlon XP chipset, and even more so when you have both the storage controller and a network card on PCI (esp. gigabit -- which you should definitely have if you're at all concerned about performance here). Note that older onboard consumer GbE solutions are almost surely PCI-based.

If you don't have/want gigabit, then get anything; it won't matter much -- because the network will be the big bottleneck in any case, the access and computations coming off the drives will be limited.

I suggest re-thinking this server, and perhaps going with a new cheap build with on-board SATA RAID with an option to upgrade down the road. A ~$100 MB + a ~$70 CPU with onboard GbE, SATA RAID, and video would be cheaper than a HW storage controller, and would still stand a good chance of matching or out-performing an Athlon XP with a crowded PCI bus, and could be upgraded down the road for a higher-end storage controller, keeping it in consumer-land with a PCIe interface, and getting a good part of its performance potential.

There are a few downsides to onboard RAID. Most of these go away if you have a full backup solution, which you should in any case, regardless of how robust your solution supposedly is.

If you really insist on a PCI HW storage controller, look at Areca and AMCC/3ware, and just check for backwards compatibility with PCI as a detail.

 

[Madwand]

I'd like to highlight one point, and so am putting it in a separate note. The main failing for RAID 5 performance is in writing. This is an even bigger problem with on-board RAID 5 solutions, because they don't spend the money/effort to optimize them for this problem, and one of the main reasons to get a separate storage controller for RAID 5.

So you will have slow writes if you go with on-board RAID 5 -- say around 1/2 of a single drive speed at best (which can get fairly slow when the drives are really crowded). But considering that a crowded PCI bus could be capping around that anyways, and that in some cases you don't need to write often at high speed, this might be an acceptable compromise for some.

 

[drumma_boy]

Ok, thanks man, i didn't realise that you could use a PCI-X card in a PCI slot.

I was also planning to get a Gigabit Network card (also PCI), which i suppose would crowd the PCI bus...

I'd prefer to just use what i've got because it's there and i don't really want to spend extra cash on it.

I can get 'Promise' products straight from our suppliers, so if any of them are decent, they'd be cheaper than anything else.

This one is PCI-X, so would it work on one of my PCI slots?

PROMISE FastTrak SX4300 Serial ATA-300 PCI-X RAID Controller, Quad Channel (32MB, levels: 0, 1, 10, 5, JBOD)

How bad do you think the performance would be if I had that and the gigabit NIC on my PCI bus?

I'd rather not go software because my CPU would struggle too much.

Is the PROMISE FastTrak SX4300 a hardware RAID card or Software based like the PROMISE FastTrak SX4310?

It seems the only difference is that the 4300 has 32MB RAM onboard.

Thanks,

Paul

 

[Madwand]

Weird...

Controller does not support use in PCI slot

http://www.promise.com/marketing/datasheet/file/FT%20SX4300-8300%20DS.pdf

This one does:

http://www.highpoint-tech.com/USA/rr2210.htm

 

[drumma_boy]

Hey, yeah, that would be perfect. Unfortunatelly, I can't seem to source it in South Africa at all...

 

[drumma_boy]

By the way, would my server handle the Gigabit card and the Promise 4310 (seems the one i'll get) on the PCI bus?

Is that going to be the bottleneck now, instead of my CPU, RAM or hard drive Speeds?

- Paul