Considering Compellent: A Fresh Approach to Storage

Posted on September 14, 2006

Some time ago I went looking for a storage solution to replace and consolidate some of my aging DAS, I looked high and low, and one name rose unexpectedly up the list: Compellent. Squarely aimed at midrange cusomters looking for high-end functionality, anyone considering EMC CLARiiON, HP EVA, and HDS should give Compellent some attention.

Compellent’s tag line for some time has been “A storage solution every company can affrod and any administrator can use”. Clearly after spending some time with the product those were goals for the product during developement because the phrase kept rolling through my head while I was using it.

I had the great honor to play with one for two weeks. Sadly it turned out to be the two weeks during which I was leaving Homestead, so I didn’t get the 2 or 3 hours I ended to really put this puppy through its paces. Reguardless, I was really excited about what I saw.

Compellent has gone in a similar direction as other storage vendors, using commodity hardware to allow them to focus on the software side of the solution. The controller itself is a SuperMicro Xeon system. Sadly there isn’t a CLI, or rather the one that exists is accessable only via console and not recommended for customers, only for remote support purposes. The web interface is really good and intuative though. Its the web interface that really delievers on the “any administrator can use” promise. There are lots of diffrent ways to look at your storage solution and modify it without the tedium found on other solutions.

In the shot above (from the Compellent web site) you can see a view I really liked, a three column display with servers (hosts) on the left, volumes in the middle, and disk on the right. This solves a common problem in enviroments where your mapping LUN’s to a large number of hosts or if you simply have a large number of LUN’s, you can see it all in a glance rather than looking a hundreds of lines of WWN’s. To make things even easier, you can group LUN’s/Volumes into “Folders” for improved organization.

The Compellent StorageCenter controller views devices as front-end or back-end. Back-end would be arrays and storage, Front-end would be servers. Because of the flexability here, you can re-purpose HBA’s between roles rather than having the roles hard-set, which means that you can use a single 4 port FC card to serve both roles.

Actually dishing out storage is as easy as creating a volume, creating a server, and attaching the two. Bam, your done!

Easy to use storage is all good and well. Sure, for a small shop with a reluctant storage administrator it’ll be a god-send, but for us hardcore storage guys, who cares right? So then, what does Compellent do that differentiates itself in the market…. the answer is the first no-BS ILM (Information Lifecycle Management) in the box that I’ve seen.

StorageCenter has an option called Data Progression, automated tiered storage. They key word here is “automated”. When you buy a StorageCenter you devide the disks you have into multiple classes: 15K Fibre Channel, 10K Fibre Channel, SATA (FATA, actually). This becomes Tier 1, Tier 2, and Tier 3. When you write data it’s stored onto Tier 1 initially. Over time (after 12 days) if a block hasn’t been accessed its migrated down, transparently and automatically, to the next lower tier of storage untill it reaches big, fat, cheap, but slower SATA disks. When that blog is again needed, its then pushed back to the top.

Lots of storage vendors are on the ILM bandwagon, and frankly this concept of tiered storage has been around a hell of a lot longer that this buzz word, but its normally a seperate activity. That is, you create diffrent volumes on diffrent types of disk and then migrate the data from place to place on your own. For most storage admins this causes a problem, what do you move and when? Some answers are simple, like archived mail, backups, old reports, etc. But what about your user data?

As a hosting provider I treat all my customers data equally. Why? Because I don’t have much choice currently. The customer who bought an account and hasn’t logged in for 8 months is being served up the same as a customer site that just got slashdot’ed. Because of that equality, I have to pay through the nose for disk thats smaller and larger than I really need because deciding who should be where is complicated, especially when things change on a dime, as they do on the net. One day my user with no hits in 5 months gets listed on Fark or something can goes through the roof. Thanks to Data Progression I can stop worrying and just let the data do what it needs to do without my needing to make the decisions. Frankly, I dig this concept because my storage controller knows alot more about my data access patterns that I do, why can’t it do something about it?

Compellent StorageCenter also does everything you expect it to do as an enterprise class solution. Snapshots (which are called “Replays”, part of the Data Instant Replay feature) are easy to create and manage, you can then replicate those snapshots to another site with Remote Replication. Thin Provisioning is also available. Thanks to disk abstraction, you can create large “Virtual Volumes” and cut host LUN’s from that, similar to NetApp Aggregates, ZFS Pools, etc… the whole “pooled storage” idea. The result of the pools being that you can stripe all your volumes across all your disks allowing volumes to be as big or small as you actually need and not have to worry about how diffrent volumes are effected by the underlying architecture.

StorageCenter, today, supports Fibre Channel and iSCSI. This is a straigh up traditional SAN solution, so there is no NAS functionality. If you want that, Compellent partners with OnStor like most other SAN solutions providers do.

Compellent is a full service provider. When you buy the solution a Compellent Engineer will come onsite to help you set it up, answer any questions you have, demo it for you, and get you on your start. The upshot is that at the end of the day your up and running and serving data, not wasting a week learning the thing. And, unlike other vendors, they engineers they have are super-kool! If your a West Coast customer you’ll get to meet Dave Washburn. Dave was great. A laid back, easy to work with engineer based in Las Vegas that made me feel right at home with the product and the company. And frankly, when you deal with a lesser known vendor like Compellent, you need that personal relationship to rely on. Dave’s awesome. When I’ve had engineers from EMC out before I could only think about what it would take to get them the hell out of my data center, so as someone who’s allergic to install service, Dave made me really glad he came out.

I’m really thankful to Rob Davis at Haberman for giving me the chance to play with the box. I wish the timing on my eval had been better so I could have posted some benchmarks and better screenshots, but I just couldn’t fit it in.

Compellent’s up-and-coming quickly. Frankly, while Pillar Data has the marketing budget, Compellent has actually got the solution. This is a company you’ll be seeing more and more in the future, so go take a look at what they’ve got to offer. You can call them at 1-877-715-3300 to talk with someone and do all that sales stuff, they are all really easy to work with so just call and chat ’em up about what you need.