Which implies that a single data read will often equate to 2 physical
IO's? With the subsequent implications for the total IOP/s supported by
the devices...

T.

-----Original Message-----
From: Bob Friesenhahn [mailto:[email protected]] 
Sent: Thursday, 20 August 2009 8:42 AM
To: Tristan Ball
Cc: [email protected]
Subject: Re: [storage-discuss] Restricting initiator resource
consumption

On Thu, 20 Aug 2009, Tristan Ball wrote:
>
> Do you know how close to the data the zfs checksum is stored? Is it
possible 
> that one FS block read will actually result in two seperate physical
IO's, 
> one for the data, one for the checksum?

I don't know exactly where the zfs checksum is stored except to know 
that there are several copies of the checksum stored on each mirror 
disk, and they are in different data allocations than the user data 
blocks.

Bob
--
Bob Friesenhahn
[email protected],
http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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