[OSX-Users] Re: Back up of Time Machine

[Steve Harris]

On 25 Sep 2011, at 10:33, Jules Field wrote:
> 
> On 25/09/2011 10:21, Steve Harris wrote:
>> Maybe there's something odd in my setup, but in the office TimeMachine (running on a Mac mini, with a firewire raid array attached) seems to create one DMG image per backup client. Rsyncing that DMG file should be easy, though it might be very inefficient - not sure what proportion of the blocks change with each backup.
> Local and network TM backups are totally different things. Local ones create a sparsebundle which involves directory hard links and so on, network ones are basically a directory full of millions of 8MB(?) files. Either CCC or SuperDuper should be able to copy either with ease, all using case-insensitive disks. Certainly don't try to copy them with Finder, that makes very hard work of the job. I always use SuperDuper, I have had a few issues with CCC in the past so steer away from it (and I have a paid-up copy of SuperDuper, so prefer to use that).

Hmm, so the "remote" backups on the mac mini are sparse bundles too. I setup the backup by mounting the mini, then telling TM to use the mounted disk as a target.

When it tries to backup to the mini, it just searches for it, and mounts the same directory (over AFS I think) if it's there.

If I manually mount the sparse bundle on the mini then it looks just like a normal, local TimeMachine directory, full of hard linked directories.

Though… thinking about it, it's been a good year or more since I poked around, so maybe one of the OS upgrades has changed the way it works.

- Steve 

> I do multiple copies of important files by copying them onto multiple Macs (using ChronoSync, which is basically a very pretty easy-to-use rsync with bells) and then do TM backups of each of the Macs which hold them. This system works very smoothly.
> 
> Some of the Macs are at work, some are at home, ChronoSync syncs work to home over broadband (about 1.5 TB in total). Not much data changes at once, so the Chronosync jobs start at 10:30pm and a cron job kills the processes at 6:30am, so they don't cost me anything.
> 
> The TM backups at home go onto different disks plugged into a TimeCapsule, so it doesn't matter if the TimeCapsule blows up, I still have the disks. When attached directly to a Mac, the TM recovery code will happily read both local and network TM backups.
> 
> All works very smoothly. Never seen a "case" problem ever.
> 
> Jules.
> 
> 
>> On 25 Sep 2011, at 01:59, Hugh Glaser wrote:
>> 
>>> Well, just as I hit "Send", CCC crapped out after copying a little bit.
>>> So now I'm trying to create an img of the folder using Disk Utility.
>>> Sigh.
>>> 
>>> On 25 Sep 2011, at 01:44, Hugh Glaser wrote:
>>> 
>>>> What do you do for Time Machine backup?
>>>> 
>>>> I am getting irritated about this.
>>>> I used to have TM on my Windows server on a hardware RAID.
>>>> So no off-site backup, but protection against device failure, and worked fine.
>>>> But I wanted to pension off the old Dell, and I have a MacMini that is running in any case (my TV).
>>>> So I bought a couple of boxes from Dabs that I could put the Sata disk in (£8.32 each, which is good for letting me use 750GB 3.5" disks on the Mac - and the box for a 2.5" is 3.80!)
>>>> The software RAID was not so good (I think I kicked out the power cord while writing), so I decided it was too fragile, and bought a 3TB disk to do the whole job.
>>>> 
>>>> But that still doesn't give me my TM backup - I need to be able to copy the TM from the 3TB to one of the 750's.
>>>> But the Finder won't let me - it reports that the disk is not suitable for copying because of case issues.
>>>> Lying piece of shit - I formatted the disk as case-sensitive just so that I could do the copy, because I had seen the message before, and in any case it is com in got a non-case-sensitvie disk. Probably about hardware links to directories, but never mind.
>>>> Is it really the case that the only way to do this is with Carbon Copy Cloner, rsync, or whatever?
>>>> 
>>>> And all this is because Apple won't let me easily do TM to more than one TM.
>>>> 
>>>> We waited years for a decent backup system for the Mac, but it is still hard to protect against device failure of the TM backup.
>>>> Oh well, at least when it is finished I will be able to have an off-site backup at last.
>>>> I suppose it will finish - it has just generated an extra 7GB of swap space preparing to clone.
>>>> 
>>>> 
>>> -- 
>>> Hugh Glaser,
>>>              Web and Internet Science
>>>              Electronics and Computer Science,
>>>              University of Southampton,
>>>              Southampton SO17 1BJ
>>> Work: +44 23 8059 3670, Fax: +44 23 8059 3045
>>> Mobile: +44 75 9533 4155 , Home: +44 23 8061 5652
>>> http://www.ecs.soton.ac.uk/~hg/
>>> 
>>> 
>>> 
>> 
> 
> Jules
> 
> -- 
> sysjkf at ecs.soton.ac.uk
>