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Re: Effects of setting linux block device readahead size

From: "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com>
To: "James Mansion" <james(at)mansionfamily(dot)plus(dot)com>
Cc: "Greg Smith" <gsmith(at)gregsmith(dot)com>, "Scott Carey" <scott(at)richrelevance(dot)com>, "Mark Wong" <markwkm(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org, "Gabrielle Roth" <gorthx(at)gmail(dot)com>, "Selena Deckelmann" <selenamarie(at)gmail(dot)com>
Subject: Re: Effects of setting linux block device readahead size
Date: 2008-09-11 05:37:09
Message-ID: dcc563d10809102237s2aa1fa09x1df9276282544342@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Wed, Sep 10, 2008 at 11:21 PM, James Mansion
<james(at)mansionfamily(dot)plus(dot)com> wrote:
> Greg Smith wrote:
>>
>> Average seek time:      4ms
>> Seeks/second:        250
>> Data read/seek:        1MB    (read-ahead number goes here)
>> Total read bandwidth:    250MB/s
>>
> Most spinning disks now are nearer to 100MB/s streaming.  You've talked
> yourself into twice that, random access!

The fastest cheetahs on this page hit 171MB/second:

http://www.seagate.com/www/en-us/products/servers/cheetah/

Are there any drives that have a faster sequential transfer rate out there?

Checked out hitachi's global storage site and they're fastest drive
seems just a tad slower.

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Subject: Re: Effects of setting linux block device readahead size
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