Time Machine fails most of the time on one Mac

Since updating to Lion and the new firmware (RAIDiator 4.1.8 [1.00a043] ) for my ReadyNAS duo one of my Macs, and only one, frequently fails to backup successfully. The error message Time Machine ultimately displays is "The backup disk image "/Volumes/ReadyNAS/Mini.sparsebundle" could not be accessed (error -1)." What is pretty strange to me is that a Time Machine volume is actually mounted when TM starts up. However it isn't on the desktop with the normal Time Machine icon it is just a generic white disk icon. And it also opens up that disk as if it was a folder. I.e. it opens up a window with the Backups.backupdb folder inside of it. Then after thinking for a long time it displays the error I mentioned above. If I manually unmount the TM Backups disk and have TM try again, and do it enough times, it will eventually work (one or more times, before failing again in the same manner).

I've pasted below the Console log output as well as the output of a ls -la on /Volumes and on /Volumes/Time Machine Backups. I found one other post on issues regarding "dissenting pid". That post is http://www.readynas.com/forum/viewtopic.php?f=71&t=56328&p=318596&hilit=dissenting#p318596. I got all excited thinking that would be my problem and solution but it wasn't. If I turn off TM the ls -la shows no entries for the ReadyNAS or Time Machine at all.

I'm completely stumped because the problem although very frequent is intermittent. There is the rare occasion when the backup proceeds normally. In fact in preparing this post the first try failed with all the details listed here. And then the second try succeeded normally. Hope someone can help with this as the machine is a Mini that mostly runs headless so monitoring the TM success is

The Console shows
12/6/11 2:20:50.143 PM com.apple.backupd: Starting standard backup
12/6/11 2:20:51.427 PM com.apple.backupd: Attempting to mount network destination URL: afp://ReadyNAS@NetgearDuo.local/ReadyNAS
12/6/11 2:20:58.024 PM com.apple.backupd: Mounted network destination at mountpoint: /Volumes/ReadyNAS using URL: afp://ReadyNAS@NetgearDuo.local/ReadyNAS
12/6/11 2:21:39.975 PM com.apple.backupd: Failed to eject volume /Volumes/ReadyNAS (FSVolumeRefNum: -105; status: -47; dissenting pid: 0)
12/6/11 2:21:39.975 PM com.apple.backupd: Waiting 60 seconds and trying again.
12/6/11 2:22:40.031 PM com.apple.backupd: Network destination already mounted at: /Volumes/ReadyNAS
12/6/11 2:23:18.365 PM com.apple.backupd: Failed to eject volume /Volumes/ReadyNAS (FSVolumeRefNum: -105; status: -47; dissenting pid: 0)
12/6/11 2:23:18.366 PM com.apple.backupd: Waiting 60 seconds and trying again.
12/6/11 2:24:18.417 PM com.apple.backupd: Network destination already mounted at: /Volumes/ReadyNAS
12/6/11 2:24:56.521 PM com.apple.backupd: Failed to eject volume /Volumes/ReadyNAS (FSVolumeRefNum: -105; status: -47; dissenting pid: 0)
12/6/11 2:24:56.521 PM com.apple.backupd: Giving up after 3 retries.
12/6/11 2:25:06.531 PM com.apple.backupd: Backup failed with error: 21

ls -la output
Mini:~ ronaldg$ ls -la /Volumes
total 8
drwxrwxrwt@ 4 root admin 136 Dec 6 14:14 .
drwxr-xr-x 34 root wheel 1224 Dec 6 14:15 ..
drwxrwx---+ 25 ronaldg staff 918 Oct 13 09:51 Funster
lrwxr-xr-x 1 root admin 1 Dec 6 14:14 Macintosh HD -> /
Mini:~ ronaldg$ ls -la /Volumes
total 8
drwxrwxrwt@ 6 root admin 204 Dec 6 14:21 .
drwxr-xr-x 34 root wheel 1224 Dec 6 14:15 ..
drwxrwx---+ 25 ronaldg staff 918 Oct 13 09:51 Funster
lrwxr-xr-x 1 root admin 1 Dec 6 14:14 Macintosh HD -> /
drwx------ 9 root wheel 264 Dec 6 14:21 ReadyNAS
drwxr-xr-x 6 ronaldg staff 340 Sep 30 2010 Time Machine Backups
Mini:~ ronaldg$ ls -la /Volumes/Time*
total 0
drwxr-xr-x 6 ronaldg staff 340 Sep 30 2010 .
drwxrwxrwt@ 6 root admin 204 Dec 6 14:21 ..
drwx------ 4 root staff 170 Jul 23 13:37 .Spotlight-V100
d-wx-wx-wt 2 ronaldg staff 68 Jul 23 14:33 .Trashes
drwx------ 2 ronaldg staff 67762 Dec 6 13:40 .fseventsd
drwxr-xr-x+ 5 root staff 170 Jul 23 14:02 Backups.backupdb

Time Machine

17 Replies

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viceroy
Aspirant
Dec 12, 2011
I am having the same problem with my iMac ReadyNAS Duo combination and have not been able to back up in a week now, any thoughts, resolutions? Cheers.
roadfun
Aspirant
Dec 12, 2011
The best thing I've found to get a backup to work is to manually invoke a backup immediately after one fails. That works more often than not.
vahn
Aspirant
Dec 13, 2011
I have the same problem.

I use the ReadyNAS duo with 2 Macs. Both Lion. One Macbook Pro (the one that fails) and a iMac (the one that works reliably). Both hard-wired.

Time Machine will mount the disk. It shows up as ReadyNAS on the desktop. I can also browse to with Finder. I can see the sparsebundle.

You could virtually copy/paste the OP thread and change the name of the sparsebundle and it would be the same post.

Even the "work-around" steps are the same. Mashing the "Back Up now" after a failure (works about 5% of the timer less).

I'd add 'Rebooting the ReadyNas' also results in getting the back-up to start to my "work-around steps" although that is not 100%.

Very strange. Did not have this problem before Lion and the new Lion-approved Firmware ... but other than that I got nothing. Very strange still that I don't have this problem on another Lion machine. I've deleted and re-created my Sparsebundle more than once "just in case" but it didn't help.
vahn
Aspirant
Dec 28, 2011
Quick update:

This problem still exists for me and the work-arounds are as unreliable as my previous message. Something new, however, is that if I am not on Ethernet and on Wifi I have a higher success rate.

Otherwise, Time Machine Preferences just spins and spins on "Looking for backup disk..." before timing out with the message:

---
Time Machine could not complete the backup.

The backup disk image "/Volumes/ReadyNAS-1/<name of my machine>.sparsebundle" could not be accessed (error -1)
...

This happens even though I'm clearly connected to the <readynasnamehere> (AFP) and can see the sparse bundles when browsing through Finder.

My sparsebundlename is my full name (not give here) but like this: David K Lastname's Macbook Pro.
My ReadyNas is named deadmau5.

Vahn
mdgm-ntgr
NETGEAR Employee Retired
Dec 28, 2011
ReadyNAS-1 indicates that you have multiple connections to the ReadyNAS share. Have you tried rebooting your Mac and trying again?
scottes
Aspirant
Jan 01, 2012
I am having the exact same problem with my ReadyNAS Ultra 6 on an early 2011 MacBook Pro. If I unmount the ReadyNAS volume, that usually works--until a few hours or days later, when the problem starts all over again. Sometimes I have to use the umount command in Terminal to unmount the disk. I also did not have this problem before Lion. (My wife's early 2011 MBP is still using Snow Leopard, and never has this problem.) So, why won't OS X Lion unmount? A possible(?) clue is that before Lion, I was also able to use TM to backup to a USB disk on Airport Extreme. Yes, I know it wasn't supported, but it would work more often than not. Now, that never works--TM won't even see the disk.
mdgm-ntgr
NETGEAR Employee Retired
Jan 01, 2012
The increased requirements for TM backups on Lion are why TM backups to a USB disk connected to an AEBS no longer works.

What version of RAIDiator are you running scottes?

Have you contacted NetGear tech support (http://www.readynas.com/support) for assistance?
scottes
Aspirant
Jan 02, 2012
mdgm, thanks for the info on the AEBS-based backups. Based on your information, it seems like there is no connection between the 2 issues.

I'm running the latest RAIDiator, 4.2.19. I've done some more research since my last post, and this seems to be an issue common to other drives, not just ReadyNAS, including Time Capsule drives. Namely, that TM isn't consistent in automatically unmounting the TM disk (sparsebundle) after a back up is complete. No one seems to have come up with a perfect solution, but there are a couple of workarounds that seem to make sense:
1) Avoid opening or using TM during a backup.
2) Exclude the location of the sparsebundle from Spotlight (in case Spotlight is trying to index the sparsebundle when TM attempts to unmount it). Similarly, some have speculated that any app that may access the sparsebundle in the background may prevent TM from unmounting the sparsebundle.

A couple of other observations: A) I haven't noticed a difference between wired/wifi. TM seems to fail about as often using either one. B) Sometimes the computer won't eject the volume using the typical right-click procedure. Then, I have to go into terminal to unmount the disk. I've done the unmount using sudo, but I did read one post where the writer suggested that diskutil would suffice. I haven't had an opportunity to try diskutil in this situation yet.

I've done #1 and #2, above, and will report later if either seems to help. If others try these, let us know your results, or other solutions/workarounds you've found.
vahn
Aspirant
Jan 07, 2012
mdgm wrote:
ReadyNAS-1 indicates that you have multiple connections to the ReadyNAS share. Have you tried rebooting your Mac and trying again?

Many times. Including rebooting the NAS itself. Sometimes it works. Sometimes it doesn't.

I am not the only Mac trying to back up to this NAS. The next time it fails I'll rush off to the other room to see if the other Mac is trying to back up.
vahn
Aspirant
Jan 07, 2012
(A) I haven't noticed a difference between wired/wifi.

It could be completely coincidental. I haven't found 100% repro steps.

It may be a fluke, but since my previous to last post I have had Wifi on and Ethernet on (I usually turn Wifi off when I am "docked" at my desk) and I haven't had the problems since.

I am backing up normally, including one 15 minutes ago. I will turn the Wifi off right now just to see. I know it doesn't make any sense.

I am going to pay closer attention to the idea that the disk isn't getting unmounted and see if I can figure out if that is also my cause, and then what conditions the disk won't get unmounted under.

David