By ahl on Dec 08, 2009
A recent StorageSearch article, Four ways to use solid-state disk, discusses various ways flash SSDs can be integrated into a storage environment. While discussing offerings from NetApp, EMC, Hitachi, and Texas Memory System among others, they singled out the use of Hybrid Storage Pools in the Sun Storage 7000 series as particularly innovative:
Unlike NetApp, Sun uses flash memory in its Sun Storage 7000 Unified Storage Systems to cache all reads and writes — not only metadata —and therefore has one of the most advanced architectures to support flash memory. The Sun Storage 7000 Unified Storage Systems run Solaris on an x86 platform with an optimized storage stack and the Zettabyte File System (ZFS) that supports a Hybrid Storage Pool of DRAM cache, SSD and mechanical disks.
The solid-state drive is situated between the DRAM-based Adaptive Replacement Cache (ARC) and SATA drives. The ZFS Intent Log (ZIL), which holds the write journal to allow the file system to recover from system failures, is written to a write-optimized SSD. The L2ARC cache comprises read-optimized SSDs to extend the DRAM-based ARC cache for read operations; L2ARC can be hundreds of gigabytes in size, and its purpose is to keep working data in memory to minimize disk access."