Time Machine volume on NAS corrupt once a month

[oreggero]

Hi community!

I own a WD MyCloud EX2 which I use for Time Machine Backups. Unfortunately, there is an issue with backing up to NASs in Time Machine and I keep getting an error message which says something like: "Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you." and that it needs to delete old backups to do so.
This happens about once in a month or two, since I have the MyCloud NAS.

Basically, it renders Time Machine useless in my opinion, since I often need to recover files that I deleted more than 1 month ago.
After searching the internet for information regarding my problem, I found out that this seems to be a very common problem when backing up to NAS. I found this tutorial for repairing the .sparsebundle http://www.garth.org/archives/2011,...ine-sparsebundle-nas-based-backup-errors.html and tried it and also the shell script that is linked in the comments below the tutorial, but both did not work for me. (And even if it did, it still would be annoying, having to repair the backup every month which takes around 6 hours.)

So, my question is, if anyone around here who owns a Time Capsule ran into the same problem, or if Time Capsules are not affected by this misbehavior?
I am considering buying one to replace my WD device, but would only want do so if Time Machine would then work without needing to delete all backups once a month.

 

[kucharsk]

I've never seen that occur with my Time Capsule.

 

[chabig]

This doesn't happen with Time Capsules. I suspect it has something to do with WD.

 

[Mr_Brightside_@]

Also never had an issue on my TC.

 

[patrickhb113]

Has happened to me twice since buying WD Mycloud Mirror.

 

[kohlson]

I was using an older ReadyNAS Duo for Time Machine, and after a few rounds of the behavior you describe, I gave up and bought a Time Capsule. Rock solid since then, I've also attached a 4TB WD to the Time Capsule, and that's been solid, too. Imho, backups are supposed to be reliable and transparent, which is true (for me) on TC, and false for the TM on ReadyNAS Duo.

 

[Belgique]

I have a Time Cap and have never, ever sucessfully restored anything.

 

[PilotWoo]

I bought a single drive WD MyCloud for this express purpose a year or so ago. Had no end of problems with the issue you describe. Sold it on eBay and bought a Mac Mini. Now use OSX Server to host time machine backups. I have had ZERO problems with it in the last year.

My advice would be to ditch the MyCloud if you can, its not fit for this purpose.

 

[grahamperrin]

Any number of things might cause an HFS Plus file system inconsistency.

Time Capsule aside

If you –

1. use ZFS-based storage;
   
2. occasionally take a snapshot (ideally when the client is not backing up); and
   
3. regularly scrub the storage system

– then regaining a consistent HFS Plus file system is as simple as rolling back to a ZFS snapshot of a good point in time.

Goodness here with FreeNAS.

 

[arggg14]

I have a MyCloud Ex4100, but I haven't had any of the issues you're describing.

 

[maflynn]

I noticed something along these lines with my Qnap NAS back in the day. I've largely stopped using the NAS for a number of reasons, but one of which was consistently incurring TM errors.

I'm not using a Drobo Mini DAS and I've not had any errors, before the NAS and DAS, I did use a TC, and that too was rock solid, but wicked slow. I opted for the NAS, for more flexibility and it was a bit faster, but I finally settled on the DAS that gives me both speed and flexibility

 

[Le Big Mac]

I get this message sometimes with an HD attached to my apple TC via USB.

 

[HvLee]

Using 2 Synology's as TC, never happend to me before. (3 macs)

 

[AppleNewton]

Generally the error occurs when an issue with network connections using back ups that way.

Refer to these:

http://pondini.org/TM/C13.html

https://support.apple.com/kb/PH11310?locale=en_US

But I have an AirPort Time Capsule that back ups everything wirelessly and I have an additional back-up USB disk connected that does a secondary back-up as well for the past 2.5 years without any issues.

 

[grahamperrin]

Generally the error occurs when an issue with network connections …

With a suitably robust NAS, the OS X client should eventually recover, without user intervention, from ungraceful interruptions to network service; and from ungraceful interruptions to file service. For the past few months I have tested Mavericks with FreeNAS, no problems from such interruptions.

 

[Moohooya]

I used to get this constantly using my QNAP NAS. After several years it finally went away, if I recall correctly after a firmware update by QNAP.

If I were to build a new backup system I would go TC and forget the NAS. It seemed cool at the time but I must have spent 100 hours over the years researching the issue, trying new ideas which never worked and creating new backups.

TC users seem unaffected by these issues

 

[gnasher729]

There are NAS's where this happens all the time. Had one at a previous job; bought an external hard drive for £30 that did the job just fine without all the trouble. With the NAS, every three or four weeks it had to make a complete backup, which means half of the value of Time Machine (having really old backups available) was gone. And of course your computer might die during the time between the last backup and the new backup and then you are stuck.

 

[smirk]

I back up via Time Machine to my own Linux server running Netatalk, which is the product that all NAS units use to provide Time Machine capabilities, as far as I know. Generally, it works well, but I have observed that it will fail in the manner you described if my Mac goes to sleep or shuts down in the middle of a backup.

Once I disabled Sleep and started checking for in-process backups before shutting down, my Time Machine corruption ceased. I've been backing up in this manner for probably 4-5 years now, and so far it has been working well. However, I will say that I tend to think of Time Machine as convenient but somewhat fragile, so I also do full backups periodically with Carbon Copy Cloner.

 

[grahamperrin]

… Netatalk … I have observed that it will fail in the manner you described if my Mac goes to sleep or shuts down in the middle of a backup. …

Which version of the OS?

Re https://forums.macrumors.com/posts/22974859 above I took an aggressive approach to testing FreeNAS, which uses Netatalk. No corruption.

 

[smirk]

Which version of the OS?

Netatalk was running on Xubuntu 12 and 13, and OS X on Mavericks, Yosemite, and El Capitan.

I don't really know what's going on here that makes it fail, but if I had to guess, I'd say that FreeNAS is tuned such that it keeps Time Machine sessions open longer, so when the Mac wakes back up it just continues where it left off. Or something like that.

Also, the TM corruption doesn't happen every time for me. Sometimes I shut down during a backup and it's fine. But sometimes it isn't.

 

[grahamperrin]

guess, I'd say that FreeNAS is tuned such that it keeps Time Machine sessions open longer, so when the Mac wakes back up it just continues where it left off. Or something like that.

I'm not aware of any tuning along those lines. https://sourceforge.net/p/netatalk/bugs/382/ was closed in 2012; it's amongst the resources that I found whilst working on an enhancment to the FreeNAS guide.

 

[smirk]

I'm not aware of any tuning along those lines. https://sourceforge.net/p/netatalk/bugs/382/ was closed in 2012; it's amongst the resources that I found whilst working on an enhancment to the FreeNAS guide.

That's interesting. I (and, obviously, others) do experience corruption from time to time. I'm not familiar with FreeNAS, but could ZFS be doing something that ext4 isn't?

 

[grahamperrin]

but could ZFS be doing something that ext4 isn't?

Yes, but I'm not familiar with ext4 so I can't say whether the differences are relevant in the Time Machine server context.

 

[rworne]

I have a Time Cap and have never, ever sucessfully restored anything.

I have not had that pleasure with my TC, but ever since El Capitan, I've been getting the same error about starting a new backup. Pretty much every time it does a monthly verification. Troubleshooting it, I discovered:

1. A failing disk in the TC, replaced the 3TB drive with a new 4TB drive. Still get errors.
2. Went from WiFi to wired Ethernet. It's better, but still failed.
3. My other Mac, a rMBP, has the same issue.

Now there is another Mac in the house that is connected to a LaCie via the lightning port. That sucker has been going for the better part of 2 years with no errors.

So now I still back up my iMac to the TC, and to another drive connected to the lightning port that I just purchased. My TC on this mac only goes back to May 22, 2016. I'm expecting yet another verification failure in a couple more weeks. I hope the external drive fares better.

 

[shaunp]

I had this years ago on a QNAP NAS when Lion was released but from Mountain Lion onwards it was fine. Never noticed a problem since then on either QNAP or Synology NAS's. Raise a support call with WD and if you don't get any joy then use Carbon Copy Cloner and just backup using this to the NAS instead as it's a lot cheaper than buying a new NAS.