Automated tiering is considered a prime feature for hybrid storage arrays that mix solid-state drives and hard drives, but it has its advantages for full hard-drive systems, too.
D4, a national e-discovery
D4 offers e-discovery, computer forensics and litigation support services to law firms and Fortune 1000 companies. Organizations hire D4 to do data collection and analytics, and post the data on a Web-based hosting platform so the companies can view what information is relevant for court cases.
"Automated tiering was a huge selling point for us," said Mark Haggett, D4's director of IT. "[Compellent] offered storage tiering and the ability to add incrementally as we [grow] and we can add storage without downtime."
D4 went looking for a SAN because its Dell EqualLogic iSCSI array was running out of space to handle its file server and Microsoft SQL database.
Haggett said he looked at options from Dell, EMC, NetApp and Hewlett-Packard for a replacement SAN array.
"We looked at all features like speed, costs and ability to grow, which was absolutely key for us," he said. "We didn't want a huge capital outlay. The main issue for us was extensibility without doing a forklift upgrade."
D4 started with a Compellent iSCSI array with about 50 TB, and it has since grown to 135 TB. The array has two 450 GB 15,000 rpm SAS drives that hold the most frequently accessed data; 12 2 TB nearline SAS drives in a second tier; and 12 3 TB SATA drives in a third. Data Progression automatically moves less-accessed data to lower tiers.
"We haven't had to purchase additional high-speed drives," Haggett said. "As data ages, it [is] moved to the slower, high-capacity disks. We can more effectively use our more expensive storage, and it helps us maximize our investment.”
He said the Compellent system allows D4 to reclaim 25 TB of storage per year, a big help when battling data growth that doubles capacity every 18 months.