Dell server performance

Chris Chabot chabotc at reviewboard.com
Tue Mar 19 10:55:01 CST 2002


In my experiance raid 1 / 10 / 0 doesnt speed up the disks sufficiently. 
What i've done on a PE that needed the IO is to talk the primary channel 
out of raid mode, and switch it to scsi mode, added a secondary scsi 
backplane & cable (so 2 disks per channel) and raided them thru linux 
(both raid5 and 0 now give me _great_ performance).

The speed i was getting was around 20 to max 36 megs a second, which has 
now gone up to 100+ megs a second.

Alternativly, some of the old Perc 2 cards were based on faster arm 
CPU's, and they gave a lot higher thruput. (it seems the embeded i960 or 
whatever controller the Perc3 is using is plain and simple not fast 
enough to handle the full max thruput of the disks).

So either softraid, or a all together different raid card would be my 
sugestion.

(I have to add i still dislike dell for having: "Very high performance 
RAID solution" on their web pages, while selling me that dog slow card).

    -- Chris

Swinefurth, Chris wrote:

>All,
>    I know this topic has been discussed before, but I'm having performance
>issues and was hoping for some help.  I would like some advise and
>suggestions about tuning a PowerEdge 6450 (4 CPU) with a PERC 3/DC in a RAID
>5 configuration.  This server is housing our VMware based development
>environment.  It works well most of the time, but it slow.  I am attempting
>to determine slow points and address them. 
>	My biggest bottleneck seems to be disk.  Was there any resolution to
>the disk performance discussions of a couple of weeks ago?
>	Any ideas what to watch?  What to articles to read?  Benchmark
>programs?
>	Currently, my plan is to upgrade to Redhat 7.2 with the latest
>kernel.  I am on kernel-2.4.3-6.  It has the megaraid driver v1.14g-ac2.
>This driver is quite old.  I am also going to upgrade the PERC firmware from
>1.57 to 161J.  The docs for 161J mention "Performance Enhancements".
>	I'm looking at CPU performance, disk, and network.  The machines
>have 4 GBs of RAM and don't appear to be swapping at all.  I'm considering
>breaking the RAID 5 set, restripping, and possibly going RAID 1.
>	Thanks for any advise you can spare,
>	--Chris Swinefurth
>	NISYS, Inc.
>
>    
>
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