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Any blocks that contain compressed data bypass the PAM or Flash Cache card

biescas
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Hi,

Regarding compression, one of our Partners has received the following reply from one of their customers:

"I was happily reading through the acceptance document until I found that the compressed data bypasses the Cache Cards (PAM), this seems a reason not to implement. Your thoughts would be of interest, have you enabled compression for any other customer and if so what were the results."

From the Data ONTAP Testing FAQ I also found:

I have a pam (or Flash cache) card in my SYSTEM. will compression have any Effect, either positive or negative, on the performance of the card?

Answer: Any blocks that contain compressed data bypass the PAM or Flash Cache card. This means that these blocks do not benefit from the performance boost that the card would otherwise provide. Any uncompressed data such as that inside volumes that do not have compression enabled will still benefit from the card.

Can anybody provide a helpful reply to the above comments?

Thanks,

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