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From James Chris Beaver <beav...@algonquincollege.com>
Subject RE: Question about disk optimization in ATS.
Date Wed, 14 Dec 2011 21:18:22 GMT
Is there an algorithm for sizing?  Is it possible to have a disk that is too large?  Is it
possible to have a too many disks?


Regards

Chris

-----Original Message-----
From: Igor Galić [mailto:i.galic@brainsware.org] 
Sent: Wednesday, December 14, 2011 4:14 PM
To: users@trafficserver.apache.org
Subject: Re: Question about disk optimization in ATS.



----- Original Message -----
>
>
>
> Thanks for the insight John.
>
>
>
> When you say no RAID of any kind – I was going to format 2 large 
> hardware raid 5 sets for redundancy. The raid 5 sets would be 
> comprised of 3 * 146GB SCSI drives (as there are two raid 5 sets there 
> are 6 disks in total). Are you saying that it would be best if I just 
> presented 6 (un-raided) disks to be formatted as raw disks?

Yes.

> Kind Regards
>
>
>
> Chris
>
>
>
>
> From: John Plevyak [mailto:jplevyak@gmail.com]
> Sent: Wednesday, December 14, 2011 4:04 PM
> To: users@trafficserver.apache.org
> Subject: Re: Question about disk optimization in ATS.
>
>
>
>
>
>
>
> Under heavy forward proxy load, ATS tends to be seek limited which 
> favors lots of disks. As ATS has its own recovery mechanisms it is 
> best *not* to use raid5 or any raid, but just a bunch of raw disks 
> listed in the storage.config.
>
>
>
>
>
> ATS needs to have small block sizes, so don't use raid or stripe with 
> a volume manager as this will degrade performance.
>
>
>
>
>
> If you use a disk which has large blocks (3GB disk) then you may need 
> to set the flag to force ATS to use a larger internal blocks size 
> which results in some waste of disk space.
>
>
>
>
>
> If you are reverse proxy and have a small working set and a good size 
> RAM cache you may not be disk limited, in which case you have more 
> flexibility. Even in this case I would
>
>
> still suggest not using raid or striping.
>
>
>
>
>
> john
>
>
>
>
> On Wed, Dec 14, 2011 at 12:09 PM, James Chris Beaver < 
> beaverj@algonquincollege.com > wrote:
>
>
>
>
>
> Hello Folks,
>
>
>
> I am looking for information in regards to the best way to optimize 
> disk in ATS. I understand that the application uses raw disks however 
> what is the best way to lay out those disks? Is it best to have more 
> than one cache disk? I am inclined to put up more than one hardware 
> raid5 volume and then format them as raw disks for ATS to make use of. 
> Is there a “rule of thumb” when it comes to disk sizing? What block 
> size is best (large of small)? For example if you have to large of a 
> disk(s) will that slow down ATS as it must spend time keeping track of 
> very large caches?
>
>
>
> Any guidance is greatly appreciated.
>
>
>
> Regards
>
>
>
> --
>
> Chris Beaver
>
> UNIX Systems Administrator, ITS - Algonquin College
>
> 1385 Woodroffe Ave
>
> Ottawa, ON K2G 1V8
>
> email: beaverj@algonquincollege.com
>
> phone: (613) 727-4723 x 5385
>
> fax: (613) 727-7719
>
>
>
>
>
>
>
>
>
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>
>

--
Igor Galić

Tel: +43 (0) 664 886 22 883
Mail: i.galic@brainsware.org
URL: http://brainsware.org/
GPG: 6880 4155 74BD FD7C B515  2EA5 4B1D 9E08 A097 C9AE



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