Storage Consolidation — Part 2 — Product Selection

  Peter Baer Galvin

Last month, the Solaris Companion covered the reasons to consider storage consolidation. A storage evaluation can reveal short- and long-term savings in cost as well as management time. The needs-analysis phase leads to a design for a consolidated storage facility. This month, I’ll discuss product selection. There is quite a bit to consider about storage arrays, SAN switches, and tape drives and libraries. The wrong choices among those options could cause serious pain in your SAN down the road.

Product Selection

Our theoretical design from last month calls for a storage SAN with network attached storage (NAS) interfaces. This design allows for servers needing maximum performance and dedicated storage to attach to the storage via SAN switches. Hosts needing to share file systems, or that are not capable of SAN attachment, can take advantage of the SAN through the NAS heads. All of the storage is thus consolidated into a set of RAID arrays that can be allocated to SAN-attached or NAS-using servers. Further, backups use the SAN switching infrastructure to allow hosts to copy their data from their allocated storage to the tape libraries without using the TCP/IP network to carry the data. Finally, replication of data is done from the production site to the disaster recovery site via storage array-based or host-based replication.

As it turns out, the design is one of the easier steps of a storage consolidation process. It is based on existing storage and future storage needs. Product selection is all about attention-requiring details.

Array Selection

The design provides the requirements for storage arrays. Selecting an array that meets those requirements may seem easy, but when intangibles such as future maintenance costs and disk drive evolution get weighed, choices get more complicated.