SSD-Accelerated Storage Arrays for the Rest of Us

It is no secret that flash memory, primarily in the form of solid-state disks, has revolutionized high-performance storage. The latest laptops use flash exclusively to essentially eliminate users waiting for data to come off the disk even when booting the system or loading large files. Enterprise and even midrange storage arrays from just about every vendor use SSDs as high-performance cache and/or automated tiered storage. The one storage category that has been lacking a good SSD story is the entry-level array.

During the past few weeks, Overland Storage and Drobo have come out with new SMB-oriented entry-level arrays complete with SSD support. These new systems bring the performance and ease of use of a hybrid array down to the $20,000 price point.

Overland's SnapSAN S3000 and S5000 are full-featured, dual-active controller SAN arrays in a 2U, 12-bay, Storage Bridge Bay-style cabinet that supports the customer's choice of Fiber Channel or iSCSI host connections over 1-Gbit or 10-Gbit Ethernet ports. Both models support external SAS JBODs for expansion and the use of 200-Gbyte SSDs as high-speed volumes. The S5000 can also use sets of two or four SSDs as a read/write cache and perform LUN-level automated tiering, moving actively used logical volumes to flash and less-used volumes down to 15K or 7,200 RPM SAS drives.

Learning a lesson from Dell's EqualLogic group, Overland includes thin provisioning, snapshots, remote replication, drive cloning and the like as part the base software image rather than charging customers for software upgrades to get these features. Based on our experience with Overland's previous products, these new SAN arrays should be pretty easy to use, especially in a VMware environment where they have full vStorage APIs or Array Integration and vStorage APIs for Storage Awareness support, as well as a vCenter plug-in for array management.

The new storage arrays are priced competitively, especially considering that Overland gives its resellers generous margins. The S3000 starts at about $14,000, and the S5000 at about $18,000, with four 1-Tbyte 7,200 RPM drives. Overland's list price for a 200-Gbyte eMLC SSD is $3,610, and $9,358 for the 400-Gbyte version.

Where Overland is moving up market from low-end single controller arrays and NAS boxes to dual controller arrays, Drobo is moving up from its Prosumer roots to the single controller market. Its latest flagship product, the B1200i, is a 3U, 12-bay iSCSI array that has all the virtues of earlier Drobo products, like thin provisioning and the easy-to-use Drobo Dashboard application for management.

Like all Drobo products, the B1200i uses BeyondRAID, which maximizes the useable space when drives of different sizes are mixed in a single array. Users specify whether they want the Drobo to survive one or two disk failures without data loss, and the system sets up the appropriate mirroring and parity across the free space on the drives.

When SSDs are added to a B1200i, the system lands all data written to the SSD tier and migrates less-used data down to spinning drives in the background. Testing by Enterprise Strategy Group shows the B1200i delivering around 1500 IOPS, with nine 7200RPM drives and three SSDs about twice what it or most other low-end SATA arrays can deliver with 12 drives. Drobo recommends using three SSDs for data protection and sells a 200-Gbyte version of OCZ's Talos with customized firmware for $1,500. Drobo has also tested and supports SSDs from Intel, Micron, Seagate and STEC. You could add three 200-Gbyte Micron P400e SSDs to your Drobo for about $1,600, though I suspect it wouldn't perform quite as well as with the Talos drives.

While expanding up into the business market, Drobo also came out with a pair of Prosumer USB/Thunderbolt devices: the Drobo Mini, which holds four 2.5-inch drives, and the Drobo 5D, which holds five 3.5-inch drives, each with an additional mSATA slot for an SSD that it will use as a read cache.

These new storage arrays from Overland and Drobo are just another sign that the combination of SSDs and high-capacity disks is rapidly replacing 10K and 15K RPM drives in data centers large and now small. Look for other players in the low-end array market to provide SSD integration, too.

Disclosure: Overland Storage has been a client of DeepStorage LLC in the past, and Drobo has provided an array for use in the DeepStorage Lab.