Hybrid Aggregates aka “Flash Pools”

What is is An Aggregate comprised of HDs&SSDs Dedicated ssd read & write cache/buffer Fast. ;) Available in 8.1

Benefits Get more out of HDD. By absorbing costly I/O that would have gone to HDD, the drives are open for more reads or writes. This translates into business value in the following ways: Change from performance HDDs to capacity HDDs (for example, SAS to SATA) Reduce drive counts to satisfy workload requirements Provide a prepopulated read cache. The data in the Flash Pool write cache is also available for reads, further reducing HDD operations.

Creating a flash pool aggr create hybrid_aggr 16 aggr options hybrid_aggr hybrid_enabled on aggr add hybrid_aggr -T SSD

Read Caching policies priority hybrid-cache set vol1 read-cache=meta (metadata only) priority hybrid-cache set vol1 read-cache=random-read (default, don’t change) priority hybrid-cache set vol1 read-cache=random-read- write (blocks added to cache for writes are immediately availble, but can be duplicated)

Write Caching Policies priority hybrid-cache set vol1 write- cache=random-write priority hybrid-cache set vol1 write- cache=none

Monitoring stats show -phybrid_aggr ssd read write read ops write blks rd cache wr cache rd cache wr cache read hit read miss Instance used cached cached replaced rate replaced rate evict destage ins rate ins rate latency latency /s % /s % /s /s /s /s aggr1_FP aggr1_FP aggr1_FP aggr1_FP