Drobo Wrap-Up

Drobo graphic It’s time to wrap-up my Drobo thoughts and observations after having my Drobo for a couple of months. I first wrote about the Drobo at the end of August. At that time I was seeing erratic performance and was less than enthused about the Drobo. Then at the end of September there was a new Drobo firmware update and I saw better and more consistent performance. (At least for awhile – more on that later).

So now it’s time to wrap this up as much as possible. I’ll start of bringing those of you who read the earlier articles up to date and then I’ll  cover my recommendations and conclusions. Let me start by getting one thing out of the way – the Drobo was never a speed demon so adjectives  like “good”, “better” or “faster” are relative terms, I’m not putting a disclaimer at every speed reference. Even if the Drobo performed at the best speeds I’ve seen published it would still be slower than my Firewire 800 connected Western Digital MyBook drive. As it is now, I’ve connected the MyBook via Firewire 400 so the Drobo and MyBook each have their own dedicated port and the MyBook gets performance better than the Drobo and at the nearly same level (better writes, slightly worse reads) as the best Drobo speeds I’ve seen published.

Getting Up To Date

Nothing much changed after the firmware upgrade until the weekend of the 4th. At that point, for no apparent reason, the read speed fell through the floor. I found this interesting because Joe commented on a previous post that he was still seeing poor read speeds after the firmware upgrade although his write speeds were OK. My read speeds were even worse, I was seeing speeds under 4 MB/sec for my set of test files (mostly files of 1GB) and speeds less than 1 MB/sec in many cases. Write speeds were also down but better than reads but erratic and about 10MB/sec I did the usual things like rebooting my iMac and the Drobo itself. I did the approved shutdowns by putting the Drobo in standby. I also let the drive sit unused (but running) for nearly a day in case there was some sort of maintenance going on. (Easy enough to do since I was traveling.) But read performance was still terrible. My X-Bench benchmarks were also way down (this was after the reboots):

X-Bench results for poort Drobo performance

At this point I was pretty frustrated with the Drobo and considered selling it for whatever I could get. I didn’t feel it was a hardware problem so sending it back for a refurb didn’t seem worth the effort. Instead I decided to make one last attempt. Since it was formatted under the previous firmware I decided to do a hard reset, destroying all the data and reformat the hard drives. This would remove all traces of the old firmware. I also removed one of the hard drives (leaving three) since it would be awhile before I needed it in the Drobo. (The reset article I link to is public at this time, but the support forums and many articles are typically behind a “owner registration required” wall.).

This resulted in my Drobo returning to the speeds I was seeing right after the upgrade. Here’s the post-reset X-Bench results:


This was an overall improvement of over 75%. Copying the files back was done at an average write speed of 23MB/sec (various size files including thousands of small ones).

But the problems didn’t end there. A few days later, while I was testing running iTunes from my Drobo, the Drobo did a spontaneous reboot and my iTunes library was corrupted. Luckily my backup was the original location so I just switched back. I was testing so I was doing a lot of copies to max out the drive. But it had been copying for only a few minutes. I guess it’s a plus, but I couldn’t reproduce the problem after the reboot.

But that put me off using the Drobo to actually open files so I moved my iPhoto library off of it. Now I just use the Drobo for backup.


One area worth mentioning is partitioning. If I remember correctly the wizard defaults to a 2TB partition during setup. The problem with this is that once you get above 2TB of usable space you’ll have to deal with multiple partitions. While multiple partitions isn’t a problem in itself I find it annoying to have a random boundary which may require me to reorganize files. Drobo does say computer startup speed is affected with larger partitions. Even if I considered this a problem I haven’t found this to be the case on my iMac with a 16TB Drobo partition. It’s nowhere near the sixteen minutes Drobo says to expect and really just a couple of minutes.

During the original install (well, my latest install) I picked a 16 TB partition for Drobo but broke that into three partitions. One 500 GB partition for Time Machine, one 500 GB partition for my iMac system disk backup image and the rest as a 15 TB partition. My reasons are:

The 16 TB partition allows me to keep adding more or larger drives without having to re-partition. Because the Drobo doesn’t pre-allocate space (it only allocates space actually occupied by files) I don’t lose any space by having the partitions. For example, my 500 TB Time Machine partition only uses 83 GB because that’s all the files need at this time.

I want the partition for Time Machine because I don’t want it to grow forever. So Time Machine sees the 500 GB partition as a limit and will go through its file deletion routine when the files reach that limit.

I use SuperDuper to clone my system disk so having a partition dedicated to that makes it easier to use. If I thought I’d be replacing my current 500GB system disk I would have made the Drobo partition bigger. Since the space wouldn’t be used if I didn’t need it I probably should have made this bigger to allow for future Macs which may have large drives. If you’re curious, I haven’t been able to boot to that partition. So far the boot manager appears before the Drobo spins up. If needed, I would copy the files the replacement disk in my system or to another external drive.

I currently have three 1 TB drives in the Drobo. If I add or upgrade drives I don’t need to repartition. I can go up to the predicted 4GB drives before running into any sort of boundary.

The Drobo Dashboard will report on what’s the real available space is. Most modern operating systems should report an out of space problem without losing any files if the space really does run out. There’s also been reports that performance drops drastically when usage tops 90%.

Managing Disks

Because of the way Drobo works you lose an amount of space equal to your largest drive. Drobo classifies it as either protecting data or available for expansion but the reason is irrelevant. This is something you should think about when planning your drives.

If you fill all four bays with drives of the same size (say 1TB drives) and you want to expand your capacity you must replace two of the drives. Replacing just one doesn’t increase your available space.

If you use drives of different sizes you can start by replacing your smaller drives first. How much you gain depends upon your specific drive configuration but you can use the Drobolator to calculate the space.

In my case I used three 1 TB drives, leaving one bay empty. When it comes times to add space I’ll add a 1.5 TB drive (or whatever is a cost-effective larger drive at the time). I’ll only gain 1 TB and will be ignoring 500GB. But then when I need more space I’ll only be pulling out one drive. Since hard drive prices drop continuously waiting until a drive is actually needed is preferred. It’s possible, that when I need it the 1.5 TB drive will cost less than a 1 TB drive costs today.


On the positive side I’m keeping my Drobo. I’ve never lost any data saved to it (if you consider the open iTunes library as not saved). On the negative side I’m using it exclusively for backups and will no longer try to run software off it directly. Basically the same situation I was in when the Windows Home Server had the data corruption bug. The speed and reliability just hasn’t been there for me to run apps off of it directly.

I like the expandability and the fact that the drives don’t have to be similar (although my WHS doesn’t need similar drives either). I also like that it connects to my Mac directly.

If I had to do it again I’d give more consideration to buying a NAS, buying second Windows Home Server (WHS) which are about the same price, expanding my current WHS (which hasn’t gone well so far) or (more likely) just hold off and stick with plain old external drives for awhile. I realize the Drobo gets lots of good press and lots of people probably use it without a problem. But with my own experience I can’t recommend it even though I love the concept and look forward to a stable Drobo.

None of the links in this article are affiliate links but if you want to make purchase (despite my experience) and support the Quest you can click on the Amazon ad below.

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