Many companies are finding cost savings and improved data management with a tiered storage approach. But before purchasing those midrange arrays, you'd better prioritize your data and study up on vendor interoperability, said
These days, fewer companies are storing all their data on expensive disk and then moving it directly to tape. But up until about a year ago, the Wake Forest University Baptist Medical Center was doing just that. "We were jumping from tier-1 to tier-4, with nothing in the middle, said Bob Massengill, IT manager at Wake Forest in Winston-Salem, N.C.
Eight months ago, it bought an EMC Clariion CX700 to create tier-2 and tier-3. Newer medical images and patient data sit on Fibre Channel drives (tier-2) in the Clariion for about a year and then less-frequently accessed images and patient records are stored on ATA drives (tier-3) in the same Clariion for 18 months or more. Tier-4 consists of a StorageTek Powderhorn 9310 tape library for archiving.
Massengill said that the urgency for tiered storage at Wake Forest was based on compliance regulations and also because the types of data on tier-2 and tier-3 were growing the most. "On tier-1, we use the high-end disk on our Symmetrix to store data that the hospital will need in the next few days. But tiers-2 and -3 are where data stays for two plus years," he said.
Massengill said that the cost savings derived from tiered storage are the lure. He estimated that storing data on their tier one Symmetrix array cost four cents per MB, but only one and a half cents per MB on the FC drives in their Clariion and a half a cent per MB on the ATA drives. This way, Massengill said, you can have "the right data on the right tier at the right time … at the right price."
He did warn that, despite application intelligence and new technologies like SATA that accommodate tiered storage, you still need to understand how much data you have and what tier it should be on and build your plan around that. "Just because the technology is better now, doesn't mean you don't have to do any planning," he said.
The challenge of heterogeneity
Robert Stevenson, technology strategist at the Oldsmar, Fla. operations facility of Nielsen Media Research, also has four tiers of storage in a heterogeneous environment consisting of EMC, HDS, StorageTek and Sun gear. Nielsen's data consists of television meters that gauge what people are watching, demographic reports and other data about broadcast ratings.
According to Stevenson, tiered storage gives you a business advantage because you can better manage how much money is spent on storage. "In our case, we store bigger, revenue-creating projects on tier one. By reallocating data through the tiers, we free up tier-1 space for more projects."
Before it implemented tiered storage three years ago, Nielsen was using direct-attached storage (DAS), and often had data sitting around that they didn't know the value of. "In a non-tiered environment, everything cost the same," added Stevenson.
The pros of tiered storage outweigh the cons, according to Stevenson, but one of the challenges is managing different vendors. He recommends studying the interoperability of vendors to make sure they are certified with other vendors.
"I like to keep it to two vendors for each tier to keep things competitive, but having too many vendors leads to distractions," he said.
Eric Lowe, technology and operations manager at Good Samaritan Hospital, a community hospital in Puyallup, Wash., is in charge of a tiered environment consisting of two Magnitude 3D arrays from Xiotech Corp., a disk subsystem from Permabit Inc. for short-term archiving and then a tape library from Overland Storage Inc. for long-term archiving. Good Samaritan is in the process of implementing a DVD library from Plasmon Plc. for off-site disaster recovery.
Lowe agreed that tiered storage introduces more vendors into your environment, and checking for interoperability is crucial. "One of my goals was to be platform independent because I know I have other systems coming online in the next 18-24 months." Lowe opted for the Permeon software because he didn't want to be tied to a specific hardware platform.