RAID options

misterp · **8th February 2007, 10:05 AM**

Gday folks,

Ive been following this up since reading about TiggerK and Impacts NAS, and decided to 'promote' an old 1.4Ghz AMD machine to a NAS for my house.
I have it connected to a central switch using a 1G Cat5e network (nice and fast).

I only have PCI slots on board (think it may even have 2 ISA slots as well, just to show how old it is!).

Ive gone and purchased a cheapish Silicon Image SATA controller (No onboard option) which has 4 SATA 150 ports on (more than enough for my needs)
Product link: http://www.siliconimage.com/products/product.aspx?id=28
This appears to have a Firmware and software upgrade to handle RAID 5, which I am toying with the idea of going with (I was going to use RAID 10, mirror and stripe), but RAID 5 gives me more storage with my 4 x 320GB SATA drives (960Gb RAID 5 vs 640Gb mirrored and striped) so Im interested in making the best use out of the disks I have, whilst still maintaining some recovery/redundancy.

If I do use the RAID 5 feature, is this what people are referring to as software RAID 5, even though its a Firmware change (so hardware??)?
Does software RAID 5 seriously affect the performace to a point where its noticeable, given that its simply going to be a NAS device, the most disk intensive thing it will be doing is to stream DIVx movies and MP3`s to my MCE box and running as Web server (Apache, PHP and MySQL), and running on an old 1.4Ghz AMD??
Are there any other reasonably priced hardware SATA RAID 5 controllers (sub $100) out there? cheapest one ive found is a Rocket, but thats over $200 (makes it worth more than the PC!), and they only seem to come in PCI-x format.

Final question, can PCI-X be fitted into a PCI slot? Ive read all sorts of reports/forums, but theres been no definative answer that I can find.

Thanks for any assistance people can give. i`ll let you know how I go, just in case this info is useful to anyone else.

Andrew

Matt · **8th February 2007, 10:24 AM**

RAID 10 is great if you can afford it. It's got the best performance as it mirrors a stripped set. However you only have access to half your available HDD space because of the mirror.

RAID 5 is a good way to go as you can loose a HDD and the array will continue to function at reduced performance. Plus you only loose 1 disk worth of available space!

To answer your question PCI-X cards cannot go into PCI slots.

Also modern day CPU's can cope with RAID5 calculations quite easily without any adverse affect to other system functions. The AMD CPU you'll be using will be fine

Cheers,

Matt

misterp · **8th February 2007, 02:48 PM**

Thanks for the reply Matt,

Good to get an answer about PCI-X and PCI, saves me buying a PCI-X card and then realising it wont work!

Does anyone know much about this card/chipset? Is the RAID 5 functionality software or hardware?

Cheers

Andrew

wicked · **8th February 2007, 10:39 PM**

Good question Andrew, as Silicon Image aren't really that clear. Reading the product brief it only mentions software RAID 0, 1 and 1+0, however as far as I'm aware the controller capabilities are not important if you're going to run software RAID as it's the OS that manages the RAID functionality. You should definitely be able to run software RAID 5 using this controller under Win 2000 or 2003.

If it were me I would go for hardware RAID 5 functionality however Matt is quite correct that the overhead of software RAID will not significantly impact the performance of your solution.

I picked up a new motherboard recently with 4 SATA ports and hardware RAID 5 for $120 so presumably you can pick up a PCI card for a reasonable amount as well.

DeadlyChicken · **9th February 2007, 02:06 PM**

Software RAID is usually a term used for when you let the operating system sort out the RAID ( using disk manager in windows for example ) you can have two drives show up in windows and make them into a RAID array using windows software. hence software RAID.

Hardware RAID is usually when the syustem has a RAID controller card doing the RAID, you have two disks in and set them up in a sort of BIOS at boot up to make one container in the aray type you want and then the operating system only ever sees the one drive ( container )

so I suspect that the card is doing hardware RAID or it would be pretty useless.

I have a 160 GB mirror in my system using the on board hardware RAID along with a bunch of other disks for less important stuff

misterp · **13th February 2007, 10:39 AM**

Thanks for the replies guys, all makes sense now.
To give others an idea of how its all gone...suprisingly well I have to admit.

As I mentioned, I had an old machine with XP professional preinstalled on it, so Ive stuck with XP until I find it cant do what I want or starts buggering up. I`ll probably use FreeNAS when it gets all clogged up and starts crashing on me.

The Silicon image SATA card is great (so far). Delivered it had an older BIOS in, which offered RAID 0, 1 and 10. I upgraded to a newer version (Floppy disks...grrrrrrrrr I HATE them!!) of BIOS available off the Silicon image website and it offered RAID 5 as an option..As you boot up, CTRL-S to configure RAID sets, selected RAID 5, configured up my RAID set of 4 SATA 320G drives, booted XP, loaded the drivers, went to disk manager, initialised it, formatted it and hey presto...a nice 900 and something Gig partition to use and abuse!!

So basically its as everyone has said, its a hardware RAID 5 SATA controller, all for $35 delivered off Ebay (although it doesnt mention RAID 5 functionality on the advert as its using an older version of BIOS).

All up its cost about $500 for the 4 drives and the RAID controller. Well worth it IMO.