Compression on the 7000
ZFS has transparent compression from the beginning, thus the Sun Storage 7000 has it as well. Dave Pacheco gives some insight into the performance characteristics of zfs compression in the 7000 series:
The performance effects vary based on the workload and compression algorithm, but powerful CPUs allow compression to be used even on top of serious loads. Moreover, the appliance provides great visibility into overall system performance and effectiveness of compression, allowing administrators to see whether compression is helping or hurting their workload.