Is it worth it to get an expensive Raid 5 Controller or opt for a fast CPU instead?

[Qianglong]

I have a delimma here. An 8 port Areca card cost around $500. For less money, I can get an good mobo + AMD X2 3800 for my file server.

Now if I get an fast CPU but a non-hardware RAID 5 card, will I still get good performance or is it that the IO processor on the RAID card will outperform the fastest CPU?

 

[ColemontHD]

Seriously, what the heck are you going to be using the raid for anyways? Are you running some HUGE file sharing website or something?

 

[HeroOfPellinor]

I'm building some servers for work on a tight budget and opted to drop the raid card and roll the money into the MB and case.

If you need a raid controller you'll know and will have no other option. If you just want redundancy, then I think the second core will easily make up for the lost CPU cycles running onboard raid. I/O Performance won't be a world of difference from what I've read.

 

[Rubycon]

RAID is for availability not performance when building most servers. The X2 is also a desktop chip not a server chip!

Non hardware parity (particularly write) performance is highly dependent on how well the XOR instructions are written in the microcode and drivers. Most are not very efficient. Using a large OS system cache and lots of physical memory can speed up transactional performance though.

 

[Madwand1]

There is a steep drop off in Windows OS and chipset RAID 5 performance -- you need to meet a minimum HW (or Linux OS) RAID 5 implementation if you're talking about performance on a GbE network.

Beyond that, I'd say it's a trade-off, with network, destination, storage, cache, and file transfer protocols all mattering.

A fast CPU will not compensate for a crummy RAID 5 implementation. Conversely, a fast RAID 5 implemenation won't help much over a crummy PCI bus / network / slow client machines, etc.

 

[HeroOfPellinor]

Originally posted by: MS Dawn
The X2 is also a desktop chip not a server chip!

True....he'll be limited to NForce4 variant server boards which have hot running chipsets.

 

[Madwand1]

Originally posted by: HeroOfPellinor

Originally posted by: MS Dawn
The X2 is also a desktop chip not a server chip!

True....he'll be limited to NForce4 variant server boards which have hot running chipsets.

If you're going to be pedantic about this stuff... there are Serverworks chipsets too.

 

[Homerboy]

Originally posted by: MS Dawn
RAID is for availability not performance when building most servers. The X2 is also a desktop chip not a server chip!

Non hardware parity (particularly write) performance is highly dependent on how well the XOR instructions are written in the microcode and drivers. Most are not very efficient. Using a large OS system cache and lots of physical memory can speed up transactional performance though.

MS, you know as well as I that you just blew his brain up talking technical like that. 😛

OP what is this file server for? If its for home use, who cares about CPU speed, you care about availability and protection of your data... thats what RAID5 is for.
I personally run a file server at home off a AMD 1600+, 512RAM and a nice, large RAID5 setup (hardware card). Previous to that it was a PIII 1ghz. CPU speed doesn't matter a lick for such applications.

 

[HeroOfPellinor]

Originally posted by: Madwand1

Originally posted by: HeroOfPellinor

Originally posted by: MS Dawn
The X2 is also a desktop chip not a server chip!

True....he'll be limited to NForce4 variant server boards which have hot running chipsets.

If you're going to be pedantic about this stuff... there are Serverworks chipsets too.

They're 939 alright, but I'm pretty sure those only work with 1XX Opterons.

 

[Madwand1]

Originally posted by: HeroOfPellinor
They're 939 alright, but I'm pretty sure those only work with 1XX Opterons.

And if you checked into this, you'd find that you're wrong. But if we were to carry on this pendantry, I'm sure you or someone else find/invent something to beat us up with, so I'll quit here.

 

[BurnItDwn]

If you aren't going to get a hardware raid 5 card, and you need the performance, Then raid 10 will probably be a better bet than raid 5. Sure you will spend a bit more on Drives, however, you won't have to worry about all the parity calculations choking up any of the busses.
Just my 2 bits ....



(Everything below this line is just speculation. I may be totally off my rocker here. I don't take into consideration the points that Ms Dawn brought up.)
If you are using raid 5 for the "most storage for your buck with still some redundancy" option, then yes, you will loose some performance without a hardware raid card, however, with a good CPU, I don't think the losses would be too huge.