Time Machine Service and 4 Bay OWC RAID Drive

Question

Level 1

11 points

Time Machine Service and 4 Bay OWC RAID Drive

I am using the Time Machine service on a Mac Mini running OS X Server. The destination drive is a 4 Bay OWC Thunderbay running SoftRAID 5 to create a 12 TB volume. The only Mac client, a MacBook Pro with an attached Drobo full of photographs, has 4 TB to backup.

The ThunderBay drive is exclusively used for network backup of this one MacBook Pro. I have set it up using v5 of the server app on the Mini, which is running El Capitain.

Here is the problem - when the initial backup starts on the client, it sees the 12 TB volume. It "prepares for backup" for 30 minutes and then fails, indicating the target volume is too small. But here is the rub -- instead of a *12 TB* volume which the MacBook Pro saw initially, it indicates that the target volume is only *2 TB* and therefore too small.

The MacBook Pro will backup successfully if only its internal drive is backed up, which is 1 TB.

I have deleted Time Machine prefs on the client. Added and removed the destination on the client.

On the server I have reformatted the OWC RAID box and added and removed it as available for the time machine service. I have three other volumes that run fine on the time machine service.

Any thoughts on how to get the client to be able to back up?

MacBook Pro with Retina display, OS X El Capitan (10.11.1), OWC ThunderBay IV, Drobo 5D

Posted on Nov 29, 2015 9:08 AM

Reply

Answer 1

nowak66 Author

Level 1

11 points

Dec 2, 2015 5:04 AM in response to nowak66

As a follow up, it now seems that I cannot create *any* working new Time Machine network backup destinations that work in OS X server -- not just the SoftRAID volume but straight single disk volumes too now.

On the OS X server, it allows me to create the destinations but when I try to use them to backup the client Macs, they fail. The RAID drive described above fails for size (12 TB volume misrecognized as 2 TB after the client "prepared for backup). I tried a single 3 TB drive as an added destination on the server and it failed too for unspecified reasons. On the server side, the correct size is recognized for the target volumes.

I also have a problem where on the server side, client backups are indicated as last backup "unknown" where in the past it showed the dates of the last backup for the client.

I do have 2 other separate 6 TB destinations that were set up in Yosemite and carried forward to El Cap which still work for backing up and showing correct size. But they also show client backup dates as "unknown".

So my question is now to troubleshoot the time machine service itself or take it down and re-create it.

Reply

Answer 2

Dec 2, 2015 6:28 AM in response to nowak66

It maybe that there is a setting somewhere limiting network time machine backup sparsebundles to a maximum size of 2TB. The ReadyNAS NV+ for example imposes a 2TB limit.

There maybe various options you could explore to change/override such a limit. This could be either in a preference file, e.g /Library/Preferences/com.apple.TimeMachine, or it could be the size limit of the automatically created sparsebundle. With regards to the sparsebundle for ordinary i.e. non-Time Machine sparsebundles it is possible to resize an image after it has been created and the same process might work on the Time Machine sparsebundle as well. If you read this it tells you how to do this. http://pondini.org/TM/A8.html

Reply

Answer 3

nowak66 Author

Level 1

11 points

Dec 2, 2015 9:00 AM in response to John Lockwood

Thanks - I will give that a try.

I Do have a time machine target on a Synology that is 23 TB that works fine. So it is a little frustrating that the tried and true Mac mini with is x server time machine backup service has stopped working.

Reply

Answer 4

nowak66 Author

Level 1

11 points

Dec 5, 2015 9:25 AM in response to John Lockwood

Trying to resize the sparse bundle on the server side does not seem to work. The instructions given here (http://pondini.org/TM/A8.html) are for the old disk util and not the one in el Cap. El Cap disk util insists that the sparse bundle be journaled to increase the size and it already is.

I just keep thinking there is some limit on the size of sparse bundles for the time machine service that has a pref setup on some screen.

Is there a hard 2 TB limit on os x server time machine disk images? Does anyone have a larger on working with el Cap?

I had a much larger backup using os x server and time machine in Yosemite (over 5 TB) but I don't have one that size in el Cap yet.

Reply

Answer 5

Jan 10, 2016 2:46 PM in response to nowak66

I'm facing the same problem using Server.app 5.0.15 and Mac OS X 10.11.2 on the server mini. The client is running 10.11.3 beta (latest beta as of this post).

Time Machine on the client gripes that the size of the destination volume is 2TB, there's way more space available than that, and backup size limiting is not turned on.

This is a new problem as of a recent update, though I'm not sure when. I previously had a much larger, successful backup of the client until the client griped that it had verified the backup but needed to start a new backup. That's when the trouble began.

I'll file this with Feedback Assistant.

Reply

Answer 6

Mar 31, 2016 2:17 PM in response to nowak66

As I type this, an iMac running Mac OS X 10.11.4 (final) made a 2.79TB backup to a Mac mini running Mac OS X 10.11.4 (final) and Server.app version 5.1.For the reasons mentioned above, it's never even attempted to make a backup before now.

What did I change? Two things, and I can't say for certain which is responsible for the success.

First, I pointed the iMac to make a backup on a 3TB Time Capsule. It complied willingly, though I never let it finish. Instead, I clicked "Select Disk..." in the Time Machine backup pref pane and selected the Mac OS X Server Time Machine destination. To my great surprise, TM pref pane asked me if I wanted to "...stop backing up to 'Backups' and use 'Data' instead, or back up to both?" It then further explained that if I chose to use both, it will "...take turns backing up to 'Backups' and 'Data'." I chose "Both." So that is a difference. (I had no idea TM would make backups to two or more destinations. Wonder when that feature was introduced?)

The other thing I did is in the Time Machine settings of Server, I explicitly "limited" each backup to the backup volume by setting "Limit each backup to 40000GB of disk space." (Select the backup destination and click the pencil to see this option.)

Since I don't know which of these two things actually made the process work, can you try the second thing I did and see if that helps, please?

/Bill

Reply

Answer 7

Apr 1, 2016 9:48 AM in response to nowak66

I have had a lot of problems with Time Machine on os X server. So much so that it has made me look for a new product. Crash plan offers a great piece of software for free. You can just download and not pay them a penny to use their backup. Just install it on both machines. It offers the added benefit that you can do unlimited cloud backup as well.

http://www.code42.com/crashplan/features/compare/

You can video the features here.

Reply