What Is Drobo?

First, let’s talk about what Drobo’s current product is and isn’t. It is basically an external USB drive enclosure for a single PC – think about your basic Western Digital MyBook or Seagate FreeAgent and you’re almost there. But it doesn’t come with any hard disks; instead, it has slots for four that you add yourself, so adjust your thinking accordingly.

OK, you say, I’ve got that. A shiny 4-slot RAID enclosure, right? Well not so fast. It doesn’t use any of the common RAID levels, and proudly so. Instead, it uses virtualization and what looks to be automated block-based data mirroring to protect the data. It appears to protect data “on write”, meaning it is ready to run quicker when you add or replace a disk. Instead of running through a time-consuming RAID rebuild, it would just copy the blocks needing protection to the new disk.

Yeah, I said virtualization, but that’s not the only enterprise storage buzzword you’ll find in this little device! It’s also got thin provisioning! No kidding – in order to deal with the fact that operating systems don’t like to see their disks grow, the Drobo just tells the OS that it always has 2 TB available, regardless of the number or size of the disks installed. This might prove disconcerting to users, though…

Data Protection

This alternative approach to data protection can lead to some strange capacity situations. Basically, the device reserves an amount of space equal to the largest drive for data protection. Note: the following examples use the weird disk industry capacity numbers, not the actual usable numbers…

Put in three 500 GB drives and you’ve got 1 TB to use (500+500+500-500). Add another and you’ve got 1.5 TB (500+500+500+500-500).

Swap one of those half-terabyte drives out for a 1 TB unit and the Drobo “reserves” half of the big drive and treats it like a 500 gigger, so you still have 1.5 TB available (500+500+500+1000-1000). This can lead to some weird situations when really large drives are mixed with small ones – A 100 GB drive and a 1 TB drive equals 100 GB of space (100+1000-1000), potentially confusing customers who just spent some big bucks on a giant disk!

This guy would be better served capacity-wise by popping out that little 100 GB disk and just using the terabyte unit, which would give 500 GB of usable space. That’s right, the unit also allows you to use a single drive, and configures it to “protect” itself! Of course, the engineer in me wonders about the logic in mirroring blocks to the same drive – protection from drive failure, of course, would be lacking, but also think of the seeking as the drive churns to write every I/O twice!

Try out the online “Drobolator” to see how it works for yourself…

Drobo Grows Up

But I digress. Just put two or more drives of similar sizes in your Drobo and be done with it. One really nice thing about the device is that you can mix and match drives as needed, swapping out big and small depending on what you have available. Mixing drive types and sizes would disagree with most RAID controllers, but the Drobo eats them up, allocating as effectively as possible.

This is probably the nicest aspect of the device. You just leave it on and connected and in use and add and remove drives according to your needs and resources. Drobo handles all the setup and configuration – just slide the drive in and you’re done. Once you’ve initially formatted the 2 TB (thin provisioned) drive, you never have to do any more configuration. Data migration is unneeded too, since Drobo’s data protection system keeps the information continually available. Start with the old 160 GB drives you have today and swap them out for 500 GB or 1 TB drives next year and everything just works.

One of the best sources for big cheap drives is likely to be those selfsame MyBook and FreeAgent external disks I mentioned above. These often go on sale at big-box retailers for well below the cost of a bare drive, and most use the best SATA drives offered by their manufacturers. The MyBook Premium ES I have, for example, included Western Digital’s impressive 500 GB Caviar SE16 drive mechanism. Purchased at Best Buy for $139, it was far cheaper than the drive alone would have been at the time. While the old Maxtor Personal Storage 3200 used a PATA drive (I checked…), the newer ones apparently switched to SATA, too, and were on sale for $79 for 500 GB last week!

I’ll Buy One When…

Despite my interest in the device, I don’t have a Drobo myself, and probably wouldn’t buy one at this point since it doesn’t really meet my needs. First, Drobo is a USB-only device for PCs and Macs. Although I bet the Linux EXT3 filesystem used by my Linksys NSLU2 home server would work, it’s not explicitly supported by the company. If it was a NAS device, serving storage over Ethernet, I would be much more interested in adding it next to the Slug.

But I’m not a typical end user – most people use a home desktop as a standalone device and would be pleased with an easy to use USB device with massive storage. One issue for these folks is that many use a laptop as their only system, moving around the house, and the chunky Drobo wouldn’t be a good solution for them.

But if you’re a Mac desktop user, Drobo looks like an awesome choice. Add Leopard’s innovative Time Machine to a Drobo and never lose data again!

One device that I would love to hook a Drobo to is my TiVo Series 3. It would be brilliant to have a super-reliable, upgradable storage system to hold video content with no management needed. But the device lets me down here again since the TiVo needs eSATA not USB storage.

Maybe Drobo 2 will add eSATA? NAS? Coffee making?

Oh, and if you were wondering what Geoff Barrall of BlueArc did for his next act, look no further than Data Robotics! Quite a change – enterprise NAS to consumer storage… Who’s your marketing genius, Geoff?

Note: Some of these links include affiliate codes that help pay for this blog. For example, buying an Amazon Kindle with this link sends a few bucks my way! But I don't write this blog to make money, and am happy to link to sites and stores that don't pay anything. I like Amazon and buy tons from them, but you're free to buy whatever and wherever you want.

© sfoskett for Stephen Foskett, Pack Rat, 2007. | Why I Like Drobo
This post was categorized as Enterprise storage, Terabyte home. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

I’ve bought two 3200′s and a Western Digital MyBook (500 GB each) over the last 9 months, adding 1.5 TB to my home environment without opening a computer case or spending a fortune. The MyBook (which has eSATA) is connected to the Series 3 TiVo, one of the 3200′s is connected to my NSLU2 for home server duty, and the other is doing backup duty.

And, yeah, the most recent 3200 had that Chinese virus problem, but Avira’s AntiVir blocked it and a quick reformat wiped it clean… It’s kind of amusing to be personally affected by a tech meme, isn’t it?

With the advent of “quick enough” USB 2.0 and blazing fast eSATA, I wouldn’t be surprised if these external drives change the face of the PC. I already know of a few folks who have switched to the Mac Mini and are hanging these drives outside instead of buying a big empty case to house internal storage. And the laptop market is booming, threatening to replace the traditional desktop PC. Perhaps the idea of a Lego brick PC wasn’t a bad one after all – it was just waiting for USB to ramp up the speed…

Note: Some of these links include affiliate codes that help pay for this blog. For example, buying an Amazon Kindle with this link sends a few bucks my way! But I don't write this blog to make money, and am happy to link to sites and stores that don't pay anything. I like Amazon and buy tons from them, but you're free to buy whatever and wherever you want.

© sfoskett for Stephen Foskett, Pack Rat, 2007. | Terabytes on the Cheap
This post was categorized as Personal, Terabyte home. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.