I would be interested in knowing the impact of a-sis on cache hit % though.  Since you’re essentially changing pointers to other instances of blocks, those de-duped blocks wouldn’t be located along with the other original blocks, so it could affect the performance of onTap’s read-ahead algorithm.

From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Willeke, Jochen
Sent: Wednesday, February 13, 2008 8:01 AM
To: Bill Holland; toasters@mathworks.com
Subject: RE: De-dup'ing Primary Storage

Hi Bill,

we have ASIS on two of our 6070's for some time. We did only few tests but could not see any direct impact on the filers performance.

We have not yet used it for LUNs so far, but would be interessted in experience with ASIS on LUNs as well.

Regards

Jochen

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From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Bill Holland
Sent: Wednesday, February 13, 2008 12:50 PM
To: toasters@mathworks.com
Subject: De-dup'ing Primary Storage

To those of you that have implemented Nearstore and A-SIS on your primary storage:

1.  Have you seen any difference in overall filer performance?

2.  If you have LUNs, how are your space savings on those volumes?

I know that enabling Nearstore does some system tweaking in the background to increase the number of concurrent backup streams that can be running, but I don't know what else it tweaks that may adversely affect performance of a primary storage system.  Afterall, it was originally designed to run as a secondary storage platform.

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