Ok, I guess I will try to ask this a bit better, or perhaps
give my 2 cents and see what folks think.
In the below example of the 4 disk raid array, my issue
is not that it is 4 disks in one, but that it is raid 5. Seeing
as R5 is not too wonderful for write intensive apps, which
includes things like swap files and the like, I would think
this *not* to be a very good setup for the OS.
Now, all you raid experts, what do you think? I have done
performance testing using homegrown apps AND fsx/memx to
get swapping to occur. I see very large loads on the system
using vmstat to monitor, with a raid 5 array controlling the OS,
/tmp and swap space. When I move swap space AND the
filesystem that I was pounding to any other raid level and
re-run the same tests, I see dramatic drops in overhead.
I would think the constant parity computations for the writes
and the large number of I/Os would offset the gains of having
a "redundant" config in this case. Sure, in a READ intensive
environment a R5 or R3/5 (my choice) would give me great
performance and redundancy, and in fact I setup most of my
OS configs with a 3/5 for the OS.
I guess, as many pointed out, the vendor would not have a clue
what I might be setting up, so a 4 disk R5 is fine and I would
just be expected to change it. Not a big deal, but I guess I
was just curious.
thanks again,
rich
At 05:33 PM 11/11/99 -0500, rich wrote:
>Thanks to all for the quick response and special thank you to
>the UK "friend" who passed me the zip file. Saved me lots
>of time since our software box is not in the same city right
>now.
>
>If anyone else didn't know the software SHOULD come on a
>floppy with the system, but if not it is on the firmware CD.
>(I never bothered to look at he firmware CD, since I would
>not think of RCU as firmware -- oh well)
>
>I am still confused as to WHY a reseller would configure a
>raid 5 array out of 4 disks for the OS? Can anyone suggest
>a benefit as to why they might have done this? Just seems
>odd to me...
>
>thanks again
>r
>
Received on Fri Nov 12 1999 - 13:38:44 NZDT