Time Machine share stops being accessible after short time

[flimflamman]

I have had multiple instances in which I create a time machine share successfully, back up to it without problem and then after a few days the share basically stops being accessible. I can see it in finder to connect to it but when I try connecting there's always a failure to connect. Not sure why this keeps happening but it makes it impossible to use UNRAID for backing up to using TimeMachine.

 

Of note I usually have my TimeMachine set to off so I can manually back up every week or so. Not sure if this makes any difference.

[John_M]

Are you backing up to a disk share or a user share? Time Machine backups to network shares use sparse bundles - folders containing many thousands of small (~8 MB) "band" files that emulate a disk image. The smallness of the band files accommodates frequent updates but sparse bundles are rather fragile and susceptible to damage even on Apple's own Time Capsule devices. If you're using a user share you might want to switch to a disk share to lessen the risk. Here's a like to a very useful site all about Time Machine: http://pondini.org/TM/Home.html

[flimflamman]

I use my cache disk

[testdasi]

Please don't take this the wrong way but you have unRAID => why not try Crashplan and/or Syncthing dockers?

 

[John_M]

I can't answer for the OP but I use Time Machine because it's integrated into the operating system and it "just works". Mind you, I use a dedicated external hard disk for each Macintosh for that purpose. I once tried backing up to a WD MyCloud and it was fine as long as Time Machine was able to do its thing every hour, but after two weeks away from home, on my return my MacBook Pro's Time Machine insisted on verifying the backups on the MyCloud, found them at fault and started from scratch. That doesn't happen if I use a real hard disk instead of a sparse bundle.

[John_M]

Is the share on your cache disk a "cache only" share, or is there the possibility that the mover could be moving your files to the array? As I mentioned above, Time Machine, when backing up to a network destination, seems to be happier when it can see the destination on a regular basis.

[flimflamman]

The share is set as use cache disk only. What gets me is that if I were to delete everything in the share and start from scratch it would work for a bit and then it just bites the dust and I can no longer connect to the share even though I can see it and I can log on using my credentials

[John_M]

The share is set as use cache disk only. What gets me is that if I were to delete everything in the share and start from scratch it would work for a bit and then it just bites the dust and I can no longer connect to the share even though I can see it and I can log on using my credentials

 

I'm not sure that I understand the bit in bold. Does "no longer connect to the share" mean that an attempt to connect to the server fails? If so, how can you "see it"? What do you mean by being able to "log on using your credentials".

 

There are several stages involved when Time Machine connects to a network share each hour and it's necessary to work out which isn't working. First, it makes an AFP connection to the server and mounts the network volume. Usually the icon is hidden and does not appear on the desktop. Next, it accesses the sparse bundle disk image and mounts it as the Time Machine destination, causing a teal coloured Time Machine volume icon to appear on the Desktop - usually called "Time Machine Backups" but you may have called it something else. Time Machine then does its backup and when it has finished it unmounts the sparse bundle image and then it unmounts the network share.

 

As a test you could try doing the volume mounting manually. Browse to it in the left hand pane of the Finder or else Finder -> Go -> Connect to server... (CMD-K) to connect to the unRAID share. It may need a user/password combination - the unRAID share should not be a public one. Does that work?

 

Next, in the Finder window, double click the sparse bundle disk image. It should mount the "Time Machine Backups" volume on the desktop. It may need a different user (I use the user "TM") and password, depending on how you initially set it up. Does that work?

 

Within the mounted "Time Machine Backups" volume you should see the usual Backups.backupdb folder in the root, just like any other Time Machine volume.

 

If all that works, unmount the "Time Machine Backups" volume. Then unmount the unRAID share.

 

Try running Time Machine again. Does it work?

 

If you can mount the unRAID share without problems - there's nothing sinister about it - it's just like any other unRAID share, then the problem is Time Machine related. Have you read the relevant section of the Pondini site I pointed you to?

 

[SnickySnacks]

My personal experience is that it can take upwards of an hour for my time machine share to come online on my macbook pro after connecting it to the network (TM share is a user share on a single disk). While this is happening the first one or two TM backup attempts will fail.

 

I usually just connect it via wifi and then leave it on overnight to do the backup.

[John_M]

I usually just connect it via wifi and then leave it on overnight to do the backup.

 

Do you find it more reliable if you use a cabled connection?

 

[flimflamman]

I'll explain a bit better what I've found.

When using finder I can see my server's AFP share. I can click on it and then see my user share or disk shares that are AFP and connect to it without any difficultly.

When I go into TimeMachine preferences I can see the AFP shares listed as Tower//share but when I try to connect I get errors and the process fails.

 

If however I connect to the AFP share using Go>Connect to Server> afp://IP address. Then I see two AFP shares in the time machine preference pane. One is for Tower//share and the other is for IP address//share. If I use the IP address one then it will allow me to enter my username and password, it connects and it backs up no problem.

 

Of note I don't leave my TimeMachine on all the time.

I just use it every couple weeks to make sure I have a fairly recent backup.

 

Currently I just set up a disk share on my cache driver for AFP/TimeMachine.

 

The issue I have been running into is a few weeks later when I go to backup again I cannot connect to my Afp share for whatever reason so I have to start the process over again.

 

[SnickySnacks]

I usually just connect it via wifi and then leave it on overnight to do the backup.

 

Do you find it more reliable if you use a cabled connection?

 

I only use it to back up my work laptop so I never bother to bring the ethernet adapter home.

Given that backing it up takes hours anyways, leaving it to run overnight once a week is no big deal.

 

Once it successfully mounts (or whatever) the time machine share, it works fine doing its hourly backups until I disconnect it and bring it into work for the week.

 

I will note that I always connect via name ("tower-AFP") and if I care, I can tell when the time machine backup is ready to work because I can't browse the sparse bundle file in the finder until it's done mounting (or whatever it's doing).

 

My issue is that once the share is mounted, unraid will continue to spin up the drive the share is on for 24 hours before the afp connection times out and the disk is allowed to finally spin down, even if my laptop has long been disconnected.

 

I mentioned this issue a while back here: http://lime-technology.com/forum/index.php?topic=41729.msg396720

But nobody seemed to care and it wasn't a real big deal to just let it timeout once a week.

[John_M]

Try specifying afp://Tower-AFP.local/share instead. The alternative, Tower.local, only supports SMB connections.

 

[John_M]

@SnickySnacks, you might want to start another thread but it looks as though your AFP session is not being terminated correctly by the client, leaving it up to the server to time out. AFP is more chatty than SMB and an open session will keep disks from spinning down.