This thing is extremely slow -- help

Have a Drobo FS with about 1.2 TB free and I’m reporting extremely slow write times. According to the AJA System Test I’m getting approximately 4.4 MB/s write and 25.5 MB/s read.

I’ve done the above test with the FS plugged into my router (a DIR-825) as well as directly into my 24" iMac and the results have been basically identical.

From the reading I’ve done on these forums, I should expect 3-4 times better write speeds than that. If I can’t improve these then I’m afraid I’m going to have to return the item.

Can anyone offer up some suggestions on things I could do or troubleshoot to improve my write speeds?

And here’s a related question: there seems to be chat on this forum from users who are using the FS with jumbo frames, but from everything I’ve read, you need a specific DroboApp to do this which is not available for the FS. Can someone kindly outline the steps to enabling Jumbo Frames with the FS and an iMac? My iMac NIC card supports JS and I’m already using Cat6 cables.

Thanks in advance.

OK so I figured out the issue – I put the MTU value as 9000 in the Drobo settings and forgot to change it back. It’s now back at 1500 and I’m getting about 25 MB/s write.

I have to say, though, that this thing still feels incredibly slow and unresponsive. Navigating folders on the Drobo in Finder is a serious pain as sometimes it takes upwards of 30 seconds to give me contents of a folder with lots of files. Similarly, as has been noted elsewhere, deleting files takes ages too. Basically, the spinning beachball never seems far away.

I’m having serious buyer’s remorse and am considering exchanging the FS for an S. Speed is ultimately more important to me than having an NAS. So my next question is: is the S going to give me a significant enough speed bump over the FS? Or is the general slowness I’m noticing more due to Beyond Raid than it being an NAS?

I am having read/write issues as well now. I changed computers, and this one no longer supports jumbo frames. I have the MTU set to 1500 on the drobo, the router, and my computer but am getting transfers of 4mb/s write and 9mb/s read. What could be causing this, any suggestions?


what kind of OS do you use?

I have tested my DroboFS with Windows7 and Linux with both protocols CIFS and NFS. I didn’t play with the MTU at all.

I don’t get the expected read speed of 40MB/s but with 25MB-30MB/s it’s still ok for home use. The write speed it’s around 22MB-28MB/s with both protocols.


Have to say, I find it very slow too in finder, getting a directory listing takes forever.

Please open support cases.

I am using Mac OS 10.6.5

If you want to install SSH on your drobo, you could try to log in and do a

cat someLargeFile.zip > /dev/null

(If you know your way around a linux shell?)

If you time this and do the maths, you can work out the max speed of your raid without going over the network. You can never expect to go over this number (or reach it either).

As a comparison, I get approx 70Mb/sec sending a file to dev/null. If I copy this file to my computer over gigabit I get 30Mb/Sec. I don’t have my SSD drive plugged in at the moment so maybe the bottleneck is my old drive.

I did another test copying 2 files from the drobo at once to two seperate drives. In this test, each copy went at 25Mb/Sec for a total of 50Mb/Sec. But since the drobo would have some extra overhead serving 2 files it’s probably still not quite as fast as my max.

I’m getting the same problems. 12.5MB/s write speed with 40.7MB/s read speed. Seems incredibly unbalanced. I have jumbo frames enabled on my iMac and Drobo FS which are both connected by a Airport Extreme.


You have to remember that when you write to the drobo its spending a considerable chunk of resources on computing the parity information so that you can recover from a bad drive. You will always have lower write speeds than read speeds. Your protocol may also be an issue. AFS (apple file share) seems to be a lot slower than SMB. If you try mounting the drives via SMB you may get better performance.

I’d agree, but I actually think theres a bug in the FS firmware because after mounting the drives in SMB my write speeds jumped to about 34.5MB/s. I then unmounted and mounted with AFS and got the same write speeds. Not sure what glitch I ran into, but it seems to be fixed now. Loving the new write speed increase.

Fascinating - I normally get 25MB/sec over AFP, but I wouldn’t mind a 10MB/sec boost over that. I’ll run some tests and see how my FS fares.

You hadn’t, by any chance, installed an app like mediatomb, fuppes, or firefly and pointed it at a very large collection of music had you? If any of these apps are scanning a directory at the time you are transferring this could suck up a lot of cycles. This would really slow down your performance. Alternate theory, when you were transferring files were you doing it as a single transfer or multiple instances? If multiple then you may have had disk contention slowing things down on both your local read and the remote drobo write.

I have this exact issue, but support has told me that it’s normal operation. (How can 30-90 seconds to display the contents of a directory, and a spinning beach ball in ALL Finder windows be normal?!?)

Can I ask you guys to try this benchmark? (Disclaimer: it is a bit complicated, but it tells a lot about your Drobo disk performance.)

With my Drobo the numbers seem pretty good (never lower than 30 MBytes/sec - average 40 MBps or better).