Analysis: How VMAXe FAST Features Stack Up With Dell's Fluid Data

With the release on Wednesday of VMAXe, storage maker EMC for the first time gives its channel partners a place at the table with midtier enterprise customers and prospects looking for high-end storage solutions.

In a prerelease briefing of the CRN Test Center last week, EMC positioned its VMAXe system as ideally suited to compete with similar mid-tier systems from Hitachi, HP and IBM, and even mentioned several systems by name. But a name that did not come up in those talks was Compellent, the enterprise storage solution developer acquired in December by Dell which may stand out as tough compeition for EMC.

Included with VMAXe is FAST, EMC's Fully Automated Storage Tiering system introduced in December. To optimize data performance in multitiered systems, automated tiering solutions provide control over where data is stored, and when and how often it moves. In talks, EMC compared its system with those of competitors that it generally lists as Hitachi, HP and IBM. But a comparison of features with Dell Compellent's Fluid Data told a different story.

By default, FAST moves data in 7.5-MB blocks, which according to Steven Ball, a corporate systems engineer at EMC, is an advantage over competitive systems that operate on much bigger blocks, some as large as 1GB. Also setting FAST apart, said Ball, is its ability to move data from one tier to another continuously, while other products restrict movement to intervals of 24 hours or more.

Such is not the case with Fluid Data, the automated tiering software Dell inherited along with its acquisition of Compellent. According to 16-year storage veteran Bob Fine, Dell's director of product marketing for Compellent, continuous migration, while possible with Fluid Data, is not be the best approach for performance optimization.

"We don't move data around every second," said Fine, "because that takes system resources," a fact acknowledged by EMC. "Based on our experience, customers don't want or need that kind of movement."

Fine said that Compellent has found that it works best to move data only once daily. "We allow control over what time data is moved," so for example, to migrate during off-peak hours. Fluid Data tracks trends over the course of 12 days; FAST analysis intervals can be as long as four weeks.

Next: EMC's Symmetrix Management Console Simplifies Setups

Compellent's software also permits tiering based on RAID level. For example, admins can opt to force certain writes to be performed on a RAID 10 array for maximum performance, then move the data to RAID 5 array in the same tier, and later move it to a RAID 6 array within a more cost effective tier.

"This would give full speed for writes, but ... not for reads because ... it's not as active anymore. We give tremendous control over how data gets written and moved." Fluid Data also supports a configurable block size (starting at 2 MB) and even permits control over inner and outer disk sectors.

Still, we found that EMC's Symmetrix Management Console offers a fairly easy and straightforward way to set up and administer these highly complex and intricate storage systems. Launched through a browser, a Java-based console presents a series of ordered icons for adding new hosts; creating storage devices, groups and pools; and for managing users and roles. We plan to review Compellent's solution at a future date.

Further simplifying setups, the management software discovers and displays service initiators for easy selection, and does an otherwise good job of abstracting most of the complexities for the average corporate IT admin while leaving them accessible to advanced users who wish to look below the surface.

For example, while most admins wouldn't know the difference between a re-balance variance and a zoning variance, Symmetrix admins know they can control the percentage of drive re-balancing when new drives are introduced to the system. "Say your existing 32 drives are full and you want to add another 32 drives," explains Ball. "You can tell the system not to let drives vary in capacity by more than, say, 10 percent from each other."

That way, he said, data is spread over time from the old drives, which are full, to the new ones, which are empty when first installed. "You don't want the old disks processing just the old data and the new ones doing nothing or just working on the new data." Ball claimed that most competitors do not offer control over this metric. As for Dell Compellent, "We've been doing that for the past five years," said Fine, and it is somewhat of a requirement for any system that virtualizes drives into storage pools, as do EMC and HP.

"I'll admit that [Compellent was] early with their automated tiering work, but we've taken the technology a lot further," said Barry Burke, chief strategy officer of EMC's Enterprise Storage Division. Since the introduction of FAST in December, Burke said "it has been the fastest growing feature in EMC's history."

Burke defended FAST's near-continuous data migration capability, which can transgress tiers as frequently as every 21 minutes, and can set priorities based on time of day. "This is a real requirement in the enterprise. Workloads change dynamically during the day, [and] if you take 24 hours to react, you've missed the opportunity."

EMC expects the VMAXe to compete with HP's 3PAR T8000 and T4000 series storage systems and higher-end models from IBM's XIV series. Compellent offers a single model that scales for needs ranging from SMB to large enterprise, said Fine.

As to omitting Compellent from EMC's list of competitors in the enterprise, Burke says it's simply because "we never, ever run across Compellent in this space."