DroboPro is here!

DroboPro is here, and it’s quite a compelling offering. It’s generating buzz (DroboPro was the number one trend on Twitter for a while on Tuesday) but is it deserving? In a word, yes. But I’m still not going to buy one!

The Drobo for Pros

Just as in Apple’s Mac and MacBook lineup, the “Pro” name denotes more of everything for the pro user or small business. The most obvious addition is four more drive slots, bringing maximum capacity up to eight 2 TB drives or a solid 16 TB of raw storage. Mix in data protection with Drobo’s unique BeyondRAID and subtract disk drive “liars inches”, and you’re left with 10.9 or 12.5 TB of usable capacity.

The difference in potential usable capacity is another Pro feature – optional protection from double drive failure. Nice! Users might be tempted to turn off this RAID-6-ish double parity protection in order to gain a little extra space, but I’d strongly suggest against that. With 8 drives spinning, the system is bound to eat a drive now and then, and good old Murphy’s Law (or the notorious bathtub curve of drive failures) is sure to spell doom for your data without extra protection. I suppose single-drive protection is acceptable for a 4-drive unit, but eight drives drives the risk of loss unacceptably high.

Around back is another major surprise: A gigabit Ethernet port. No, the Drobo Pro doesn’t incorporate the DroboShare’s NAS technology. Instead, the company added a simple and speedy iSCSI stack, bringing some serious performance potential to “the little drive array that could.” The company says that a gigabit iSCSI connection pushes nearly 80 MB/s, easily tripling the throughput of the system’s FireWire 800 or USB ports.

PC owners might be put off by the lack of an eSATA port, but they would be wise to use iSCSI instead. Warning: Watch out for the limited performance of low-end gigabit Ethernet switches! Just about any iSCSI initiator ought to be able to connect to the Drobo, and Windows users will happily use Microsoft’s solid and free software to connect. But iSCSI on the Mac is another matter, and Drobo dropped a bombshell here: They cooked up their own simple software iSCSI initiator for OS X and are offering it free to all! This is shout-out-loud news since functional OS X iSCSI software costs hundreds of dollars from other vendors and Apple’s built-in Leopard iSCSI support is AWOL even in the latest Snow Leopard builds.

On the software side, Drobo remains amazingly simple to configure. You won’t find even a dozen buttons in the management interface, and no tuning or configuration is required. The software continues Drobo’s tradition of presenting all attached storage as a 16 TB drive, regardless of how much is really installed. This means that capacity can grow and shrink as drives are hot-swapped in and out without the connected server even noticing. The Pro does add one new trick: You can tell it to present up to 16 of these fibbing drives to the attached server if you’d like to segment your data a bit. Pro owners can also disable drive spin-down for server use.

Drobo is positioning the Pro model as the perfect small business storage system, and I certainly wouldn’t hesitate to recommend it as bulletproof small-office storage. By far, DroboPro is the simplest storage device to manage, expand, maintain, and install. It’s cheap compared to other 8-drive RAID systems at $1200 empty and can grow to meet the needs of a dozen folks, or one especially productive one, with ease. Connect a Drobo Pro to your Mac Pro and you’ll grin like a little girl who just got her very own pony!

No Drobo For Me

Although I love DroboPro even more than Drobo classic, it’s not for me. DroboPro is exactly what the majority of folks need, but its intentional simplicity means that it wouldn’t work in my home office environment.

You see, Drobo can still only be connected to a single computer. Although the Pro unit sports a total of four ports on the back (two FireWire 800, one USB 2.0, and the gigabit Ethernet), users must pick one and ignore the rest. Even the iSCSI support is limited to serving up a single target. This is not a home SAN. It’s not even suitable as a Time Machine target for two Macs.

Yes, you can share the capacity of a Drobo with NFS, SMB, or AFP using a computer or DroboShare, but that’s not what techies like me want. We want to share its storage directly among a few computers, something the Drobo Pro teases with its iSCSI support but refuses to deliver. And don’t be fooled: The second FireWire port is for daisy-chaining other FireWire devices, not connecting multiple systems.

Do you want to support a mail server and a file server in your small office? Buy two Drobos or combine them into a single computer. But I’m not going to do this at home. Data Robotics also hasn’t yet logo-qualified the Drobo Pro for Windows but it worked fine in their demo. I’d love to see ESX and Hyper-V qualification, too!

Finally, note that not all of these features are trickling down to the 4-bay Drobo. It is obviously not iSCSI-capable, since it lacks both the gigabit Ethernet port and dual-core processing muscle of its big brother. Dual-drive data protection, drive spin-down disable, and multi-volume capability are missing as well, though I’d love to see the latter especially.

Despite these limitations, I would not hesitate to recommend Drobo and DroboPro as the best simple storage available.

© sfoskett for Stephen Foskett, Pack Rat, 2009. | Drobo For Pros But Not Me
This post was categorized as Apple, Personal, Terabyte home. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

Spun Down

Although ZFS’ universal storage pool with non-RAID is a great concept, it stands in the way of at least one (sometimes) desirable storage technique: disk spin-down. Put simply, since every disk contains metadata, all disks must always be spinning. This issue is by no means a ZFS-only problem, though – certain vendors tout the (laughable) greenness of their storage systems, while hoping that the average user won’t notice the truth: That a disk simply cannot spin down while any part of it is in use. This means that tacking spin-down onto a regular storage array is like painting it a different color: There is no benefit whatsoever to the average user. Sure, a few non-provisioned drives might spin down, but what are you doing buying a lot of non-provisioned drives anyway?

The solution has always been right in front of everyone: Develop a new type of non-RAID with enough intelligence to allow drives to spin down when not used. This is what COPAN Systems did with their MAID technology: Invent an entirely new storage array, with integrated data protection and management techniques that allow alive but not active drives to spin down. Spin-down is not MAID any more than a bicycle is a Ducati.

Let’s make one thing clear: It’s really hard to reduce the power demands of storage devices. Disks guzzle watts like few other data center devices, and enterprise storage uses lots of disks. Lots of vendors are looking to hop onto the green storage bandwagon, and they all seem to realize that bringing some intelligence to power management by enabling spin-down is an open door. But it’s awfully hard to maintain performance and data protection when disks are spinning up and down all the time.

One element of the greenByte story is the way in which they have tweaked ZFS to allow disks to spin down. They limit the metadata updates to just a few disks, so the others can be idled when no access to them is made. The company suggests scheduling this for off hours to minimize latency as drives are brought back online, an approach that is less than optimal from an energy perspective but demonstrates that they understand just how difficult this problem is to crack. The core is there, however: They have integrated the data protection and storage management elements to enable spin-down to be practical.

Compressed

Another major storage industry theme of the last few years is deduplication of data. An advanced (or devolved, depending on your perspective) form of compression, deduplication allows a storage array to store duplicate data more efficiently, reducing the amount of capacity required for some applications. Data Domain is top-of-mind in this space, but just about everyone now offers some form of deduplication technology.

One major roadblock on the way to deduplication (or compression) nirvana is performance. Simply put, it’s really really hard to process data on the fly without affecting performance, especially as data scales up to the multi-terabyte range or as systems scale out to include multiple devices. One approach to tackling this issue is post-processing dedupe, which accepts incoming data in the normal way but goes back and processes it later to remove duplicates. This is the method NetApp uses, and they have leveraged it to become the first vendor to support deduplication of production applications.

Predictably, deduplication is another technology integrated into greenBytes’ “ZFS+” technology. They claim that they can handle inline compression at wire speed, and also claim deduplication inline. It’s not yet clear exactly what the difference between compression and deduplication is to the company, or just what kind of performance their inline technology will yield, but it’s certainly nice to see this tech integrated with ZFS!

Thin is In (the House!)

greenBytes gets closer to enterprise storage bingo by adding thin provisioning to the mix. Actually, as the company’s CTO was quick to point out, they had to offer virtual or thin provisioning to enable the rest of the system to function. When your storage is sliced and diced by their Cypress array, the only way to present storage is with a wink and a promise of capacity to spare. Thankfully this is not the core of their pitch, however.

The company also promises snapshots and CDP replication, all leveraging ZFS at the core. All they need to add is tier-0 solid state storage to get five chips in a row without even using the free space! Although greenBytes is using Sun’s Thumper chassis currently for their Cypress array, their core technology is the ZFS+ software, and I expect we might see this mixed quite differently in the future. This is a software company, not an array vendor.

All considered, greenBytes has thoroughly broken the link between physical and logical storage, and I applaud them for it. This is exactly the kind of storage revolution the industry needs right now.

© sfoskett for Stephen Foskett, Pack Rat, 2008. | greenBytes Embraces and Extends ZFS
This post was categorized as Enterprise storage, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.