Hard disk bottle neck.

[Danny Do]

Hi Diego,

The reason I use RAID5 because I don't want to waste too much space on redundancy whilst taking the advantage of read. Over 99% of disk access are expected to be reading. 

I could split to 2xRAID5 but I will have difficulty with file management later. Furthermore, the system would use 2 disks for parity. I don't want to lose too much space. 300GB at 10K SCSI disks are still very expensive. :(





-----Original Message-----
From: owner-freebsd-questions at freebsd.org [mailto:owner-freebsd-questions at freebsd.org] On Behalf Of Diego F. Arias R.
Sent: Sunday, 28 September 2008 11:25 PM
To: Bill Moran
Cc: Wojciech Puchar; Danny Do; freebsd-questions at freebsd.org
Subject: Re: Hard disk bottle neck.

On Sun, Sep 28, 2008 at 11:17 AM, Bill Moran <wmoran at potentialtech.com> wrote:
> Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl> wrote:
>>
>> after you recompile the kernel with that patch, check your disk
>> performance in some directory consisting of many large files
>>
>> cd that_dir
>> for x in *;do (cat $x >/dev/null &);done
>>
>> while running systat,:vmstat on another console
>
> More specifically, do this before and after you make the change, to
> demonstrate whether or not you actually fixed the problem.
>
> --
> Bill Moran
> http://www.potentialtech.com
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>

do you check gstat?

If the patch dont works, maybe yoy may try to split the raid (2 raid
5) or better use a raid 10. The raid 5 isnt a top performance raid.

-- 
mmm, interesante.....
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