[NBLUG/talk] A Non-linux Hardware Question

Lincoln Peters sampln at sbcglobal.net
Fri Dec 30 22:49:48 PST 2005


On Friday 30 December 2005 15:28, Stephen Cilley wrote:
> I'm swapping out my hard drive for an exponentially
> more expensive solution.  I'm thinking about doing two
> of these in mirror:
> http://www.newegg.com/Product/Product.asp?Item=N82E16822136003

*drool*

(Not that I'm questioning Bob's comment about the reliability of hard drives 
shipped by NewEgg; that just looks like a REALLY nice hard drive.)

> If that's a horribly off idea then feel free to
> comment, but that's not my real question, my real
> question is this: people have told me in the past that
> the OS should be on a separate hard drive, but I can't
> remember, is the drive supposed to be ultra fast or is
> it supposed to be cheaper/slower.  I was thinking
> about doing a 4.2 KRPM drive or whatever, just want to
> know what I should use for the OS.

What I have on my primary system is a set of three drives and two RAID arrays 
as follows:

hda:	total 300GB; 50GB for raid #1, 249GB for raid #2, 1GB for swap
hde: total 300GB; same layout at hda
hdg: total 250GB; 249GB for raid #2, 1GB for swap

"raid #1" is a RAID-1 (mirrored) array containing my root filesystem, with a 
total capacity of 50GB.  "raid #2" is a RAID-5 (distributed parity), with a 
total capacity of 498GB.  I have 3GB of swap.

Because of the way it's laid out, if any one of these hard drives fail (and 
they have failed in the past), it's possible that one or both arrays will be 
degraded, but neither will fail unless two hard drives fail simultaneously.  
In fact, as long as the swap partition doesn't fail on a hard drive while 
it's in use, the system will keep running just fine with one failed drive 
(and if I was *that* worried about uptime, I could make the swap into a 
RAID-5 array, at the cost of some response time when using the swap).


If you install two 320GB hard drives, you could partition each of them 
identically, with separate partitions for the root filesystem, /home 
directory, swap, and whatever else you need (I'd probably go with 50GB for 
the root, 169GB for /home, and 1GB for swap; you could ).  Then join each 
partition on one drive to its counterpart on the other drive in a RAID-1 
array (except for swap, unless really you think you'd need redundant swap).  
You won't get the performance boost of having different filesystems 
distributed across different hard disks, but the RAID-1 implementation in the 
newer kernels should give you some performance gain, and the failure of 
either drive will not cause data loss.

-- 
Lincoln Peters
<sampln at sbcglobal.net>

We all dream of being the darling of everybody's darling.

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