SATA Raid

Nicholas Leippe nick at byu.edu
Tue Mar 15 12:26:29 MST 2005


On Tuesday 15 March 2005 12:03 pm, jeff wrote:
> At work we are going to set up a new fileserver Linux w/ Samba.  Get rid
> of the last @#^$%@ windows server finally :)
>
> We are looking at using a areca SATA RAID controller with lots of
> drives.  I have never used SATA RAID, only SCSI.  What kind of
> processor(s) and RAM am I going to need for this?

What kind of load?
How big is the average working set?
How big are the files?  Generally very large?  All small?

I would speculate that if it's (true) hardware raid, then the only real load 
on the cpu is the fs layer and the network stack--thus as long as it is fast 
enough to keep the I/O queues busy and the packets flowing, it's enough.

As for ram--quantity of ram and your I/O performance determine your 
latency--ie cache hit or miss.  You'll need to know your load patterns for 
this.

If it is not hardware raid, that's a whole different game--you'll need to 
consider how many cycles are consumed in the md layer, and consider SMP to 
reduce the additional latency incurred by them.

What hardware was the windows-box being which is being replaced using?  Was it 
sufficient for the load?  That's probably your most useful metric.


-- 
Respectfully,

Nicholas Leippe
Sales Team Automation, LLC
1335 West 1650 North, Suite C
Springville, UT  84663 +1 801.853.4090
http://www.salesteamautomation.com



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