PAM Card within SAN Dedupe

[chriskranz]

From previous questions around the PAM card, I'm sure there will be some general benefit of using this within a SAN deduped environment, but is there anyway to factor in how useful? SAN tends to be more random IO, will this show tangible benefits for PAM usage? And to follow on from that, if there is a benefit, can we realistically expect to use SATA within this environment? Are there any benchmarks to help with this?

[bikash]

PAM will be very effective if disks are greatly bottlenecked due to random read workload. SATA and PAM could be an ideal combination. PAM will reduce the number of disk spindles and compensate to the high disk latency of a SATA disk. In your deduped environment PAM will also help to have just one copy of the data block in the buffer rather than having multiple copies.

[amiller_1]

This was posted in another thread but I thought it might be good to post here as well....

http://blogs.netapp.com/dropzone/2009/06/dedup-for-speed-higher-performance-through-deduplication.html

...given that a PAM card amps up this concept a good deal.

[amiller_1]

Also, while it's not SAN-specific, TR 3744 shows some very nice details here.

The NetApp Performance Acceleration Module in File Services Workloads

In short, to get 40,000 IOPs you can use either 224 15k FC spindles or 112 SATA spindles + a PAM card.