5N very slow accessing time machine sparse bundle

Hi all,

I had an abrupt hard drive failure on my iMac recently. That drive has been replaced and I am working on restoring from my Time Machine backup saved to my Drobo 5N. Backing up has been going smoothly and reasonably fast. It improved a few months ago after I replaced a low quality Ethernet cable to my iMac.

I was not able to mount the Time Machine share via the command line for restoration. I installed a fresh copy of OS 10.11.6 and, not finding a better way to do it, loaded up the sparsebundle file and have transferred files manually. The initial loading of the disk image takes a while, but it is large and complicated, so I found this unsurprising. Once loaded, I was able to navigate to the latest backup and moved a number of folders over to my new hard drive. Here, each folder had a delay to load, but it was on the order of 20–60 seconds. Once I began transfers, they went at reasonable speeds.

At some point, an installation required a restart, and the disk image was unmounted. Since trying the same sequence again, I am finding load times incredibly slow. Transferring about 3 GB is going to take 12 hours plus hour or two for the disk image to load and for navigation through just a few folders.

I have the latest copy of 10.11, Drobo dashboard, and 5N firmware and none of those things changed from the initial transfer to now. One of the things that may have been installed in between is Sophos Home antivirus software. I have not found it to be a performance problem in the past. The rest of the recent installations don’t seem like they would cause this behavior. I also tried restarting the 5N and Mac at different times.

Does anyone have some thoughts on why things are slow and how to improve them? The initial experience was reasonable. This one makes me think I need to consider a different back up strategy. Intact and nearly unavailable is not the best backup.


hi scott, if your are restoring things just locally from the drobo, and without internet etc, then it might be good to try disabling that antivirus, at lease until after the resorations are complete, just in case it is slowing things down any further?[hr]
for backups, does acronis support mac?
on windows at least, it works a treat with my Das drobos, as it simply boots up from cd, mounts the drobo via usb, and lets me create a huge 800GB image. (there are incremental/differential options too but just as an example of a big file working ok)

Hi Paul,

I came to the same conclusion as I was typing my question. Last night I restarted the Mac and disabled the antivirus software. The speed experience seemed similar to the first set of transfers. I am going to do some more today and will report back.

Thank you for your suggestion!

Update: I am still finding transfers to be very slow. It’s going to take 3 days to move 550 GB, this does not include the half day to just start the copy routine. I accessed other shares on the 5N just for testing and these seem to be responsive. I did not copy anything from these shares, but I expect they would proceed faster. I don’t know what it is about this Time Machine backup that is now so slow (initial work here was reasonable).

Has anyone used a different backup method like Carbon Copy Cloner with a 5N? I am thinking maybe the 5N and Time Machine are not best buddies (Time Machine backups have proceeded much faster than the current copy speed).

hi for your previous post - cool great minds think alike as the saying goes :slight_smile:
but for time machine, is it something to do with the mac not being in a normal mode?

for example, if i use windows in safemode, everything takes ages (especially to load)
maybe for the mac, it is a combination of the mac recovery mode, (or as i recently learned, something new about the way the mac now encrypts network connections could be slowing things down?)

btw there is a good site here that i heared about from another user johnm which may help:

Update 2: I had the previously mentioned transfer fail (probably due to a corrupt file) and it was running very, very slow. It was going to take 3 days to move about 500 GB. You could hear that it the Drobo was not trying very hard. I have Western Digital RE drives for my 5N and there was hardly any noise at all. Maybe a brief drive access every 5 seconds, rather than a sustained access sound like “normal”. They are not quiet drives.

I tried rebooting the Drobo and starting the process back. This time things worked as I expect them to. The 500 GB transfer took about 2.5 hours. Moving through the file path in the sparse bundle file was pretty responsive to navigate through. I got another folder section going now which will take about 30 min for 30 GB, which is completely reasonable.

I don’t know why this reboot was more effective than the last one, but I know what to try next time. I did avoid mounting extra shares, but this has not affected things in the past when operating normally. In fact, a NAS should be able to handle multiple queries. I was scoping out Synology products today in frustration. The devices are not cheap for Drobo, Synology, etc., but disk pack is even more. If providing high-quality disks is not an advantage with a given device, then maybe giving another a try makes sense. My Drobo has never lost data, which is to its credit, I guess.

I edited a typo from my first stab and have since started multiple streams and all is happening at the saturation of the network (1 Gigabit Ethernet), so it looks good today.

thanks for the info, that is good to know, and am glad things are working again ok for you (at least today) :slight_smile:

there is a fair amount of info on the forums about which drives to use and rpm spin speeds, and msata cards etc,
and while i may not remember everything, my gut feeling is essentially this: (i might make a new post with the info too)

for casual users, (like me and the das models),
the highest spin rpms are not required,
though DDR is recommended,
(ive still been able to do some low-medium quality video editing / live recording, and hq live audio)

for users (nas or das), who work with fairly large files,
msata may not improve things that much,

for users (nas or das), who work with lots of smaller files, like office documents, photos, smaller media etc,
msata is most likely to improve those things

for semi-pro, nas or das, (or also for people who are having multiple users, or often adding or upgrading drives etc)
higher spin speeds , and msata where smaller files are used.

there are business end / pro models, which im still learning about,
though in all cases, if DDR is possible, i would recommend it.