Time Machine backups

[philharve]

Hi Jacko1

Since I last wrote I have tried using other backup applications to see it they would transfer data to the NAS and without exception they have all worked. However, since backing up over a wireless link can easily take a week, or more, I have aborted the backup and started over again hoping I will spot something in the backing up process that will lead me to a solution.

Every now and again I try drag-copying files between my MacBook Pro and NAS and it never fails to work. The copying is relatively quick too. So this begs the question, 'why does drag-copying work and Time Manager backups don't, at least not on my system and from the evidence a great many other systems too?'

A few days ago I read an article concerning what can make a TM backup fail. The troubleshooting advice stated that the disk formatting of the NAS should be identical to my MBP. Using Disk Utilities I was able to determine that they are different, my MBP is HFS+ Case-sensitive Journaled and the NAS Shares are HFS+ Journaled. This distinction might be important but I need to do more research.

However, the TM backups themselves are 'sparse bundles' and I have found numerous Apple references to them being used on directly-connected drives (USB, Firewire). I assume sparse bundles are also used for network drives but I have yet to read corroberating evidence that TM will happily backup over a network. This brings us back to the point you make concerning lack of TM support for network drives. We need to know if this statement is true, or not.

I have gleaned sufficient information concerning 'sparse bundles' to make me just a little suspicious. I can envisage a situation in which the sparse bundle might become corrupt and lead to the situation I have called 'overrunning' in which the backup appears to complete but then continues, apparently without end.

I have begun testing with a second MBP (Lion) and have attempted TM backups with it to the NAS. I can see a separate partition for each MBP backup using the WD Dashboard (UI) but how are these partitions formatted? The back up results obtained with my second MBP are not that dissimilar to my older MBP (Snow Leopard) which tends to rule out both my Macs and TM as being responsible for my backing up problem.

I, too, have used directly-connected external drives with both MBPs and TM and never once had a failure. However, introduce a network and things start to go wrong with backing up but not with drag-copying. I tend to believe that if drag-copying works to a NAS then we can rule out the network+router as the source of the problem, with or without wireless.

Logically, the only component that remains untried is the NAS itself. Try as I may I cannot fault the UI. As they say, 'it does what it says on the label'. 

I would like to think that there is a hithertoo undiscovered firmware bug in the NAS software but if so why do some users of the MBLD (NAS) say it works just great! I feel sure there is some subtle difference in my system that causes the backing up to fail. I am not saying my system is faulty, I am saying it is different and the WD firmware fails to take account of it.

I have written to WD Support many times and now they seem to have stopped replying. Is it because they are bored with me or is it because they are fending off a huge backlog of problems and they have not had time to get back to me?

[philharve]

UPDATE

I found this reference to using TM to backup over a network ...

http://www.levelofindirection.com/journal/2009/10/10/using-a-networked-drive-for-time-machine-backup...

... which although submitted in 2009 may still relevant. It is just possible that WD has implented this workaround and the information maybe out of date. But who can say?

[philharve]

UPDATE

The thought has just occurred to me ... if the amount of data I need to backup was considerably smaller than the actual amount of data I need to backup (400GB) then a TM backup might be successful. I know that some owners of the WD NAS have encountered no problems but I never questioned the size of their intended backup. I have watched a TM backup progress (I use Net Monitor) from initiation and it 'seems' to progress normally but after a while it 'seems' to falter (sparse bundle corrupted?) and the backup rate drops dramatically. This faltering could occur after several tens of gigabytes have been transferred but falter it always does.

The above link (previous post) suggests using a cable to make the initial TM backup and maybe reverting to wireless afterwards for the smaller incremental backups. But notice there is a workaround if switching between Ethernet and wireless involving MAC addresses!

Evidently the longer a backup takes the greater the likelihood that the backup will at some point be corrupted. When corruption occurs the only recourse is to delete the previous backup and startover again.

What I cannot fathom is why corruption can occur in the first place.

[Jacko1]

Hello Phil,

I’m convinced there are a number of issues here.  I myself have read articles stating you should always carry out at least your first TM backup via Ethernet.  However, I can’t help but wonder if that advice hasn’t been superceeded by the implementation of Lion?  My reasoning for this is because the newly released MBP has neither optical drive or Ethernet connection.  The only option must then be wireless for that particular Notebook.  I have only ever used Ethernet for my MBL, indeed, I have wireless disabled on my iMac completley.

I think Western Digital must know what lies behind these issues.  They have afterall I’m sure lots of logs from MBL users. Surely they have analysed them in detail so must see a general pattern?

The difference with MBL since I’ve started to backup to a dedicated USB drive for TM is amazing.  When I tried to use MBL for TM the darn thing was all over the place, it rarely slept, even when using TM Editor to schedule just one backup per day.  Even coughing near it felt like it was enough to wake it and when I could get it to sleep, most of the time it took twenty to thirty minutes at least before it would sleep.  Now, since I stopped backing up to MBL it sleeps most of the time and once woken will often sleep again with around ten minutes.  I’ve also noticed when accessing files remotley (but on my local network) that file access is almost instant.

Certainly for the single MBL I don’t think it should be marketed as a backup solution and NAS.  Backing up to the same (single) drive where you are storing your data is asking for trouble in the event of failure.  I think WD should market this as backup or NAS and should warn users about the dangers of using both as a one stop solution.

[Jacko1]

Update - As I already have a full TM backup on my MBL (though I haven't been using this method for about a week now) I thought I would keep it current by updating it once a week.  I started a manual TM to MBL backup just after lunch, the backup was only 2.3 gig.  The backup started without incident and raced away to 460 mb and there it stayed, for around 45 minutes.  I then cancelled the backup and started my iMac in safe mode in order to clear out the cache etc.  Following restart of my iMac I rebooted MBL and started the process again.  Although it has performed the backup, the progress was erratic and not nearly as quick as when done on the WD 5400 rpm usb drive.

From everything I've learned and done with MBL I would say that TM is the real issue with this drive being used successfully. Wherever the fault lies i.e.. be it Apple or WD, the fact remains that MBL and TM just aren't compatible as things currently stand, further development is urgently required.

[philharve]

Hi Jacko1

We have both arrived at the same general conclusion but via separate routes. I guess this problem is a WD and / or Apple issue!

I was going to buy a second WD drive, an MBL would do, for the storage of safepoints offloaded from my 3TB MBLD but from your comments I think I had better defer that decision to another time.

I am still able to backup and clone both MBPs to external USB drives without problem. When I purchased the NAS I have visions of automated TM backups every hour but I am having to put that dream on hold too.

I wonder if WD staff scan this Forum looking for potential problem areas or do they only act upon issues reported to WD Support?

[Jacko1]

Hi Phil,

I'm quite sure WD staff read these forums.  I'm also absolutely convinced they are well aware of this issue with TM and MBL as it's not new if you read these forums.  There appears to have been many promises of "jam tomorrow" yet still we wait.  I intend to look at forums for other such devices to see if they too have problems with TM.  I think as usual with these third party developers far more R&D goes into the Windows side of things rather than Mac - yet we are paying the same for the product so somewhat unfair.

I like you continue to make flawless TM backups on separate USB external HD's though this isn't what either you or I envisaged.  As soon as I re-connected my external USB drive MBL behaved impeccably and went straight to sleep.

[philharve]

UPDATE

I have been contacted by WD Support and been given the services of a dedicated support technician who requested I provide him with a 'system log' from my NAS. This was a 5.4MB file which I attached to a progress report before forwarding to the technician.

He also requested I perform a Factory Restore which will make it the third time. The previous two restores made no difference whatsoever. The latest restore was completed in 27 hours and I have had to setup the NAS once again. It is much easier the third time. The NAS is currently converting itself to RAID 1 operation (another 6 - 10 hours) and I have discovered that the NAS can be used for storage during the rebuilding phase.  

But I have noticed a difference, a small but noticeable improvement to the wireless performance which has increased by around 25 percent. I reported earlier that I had switched the NAS from DHCP to Static IP addressing during which I selected my own fixed IP address (192.168.1.201). This step did not in itself resolve my problems but the thought has since occurred to me that maybe I should have reinstalled the WD Quick View software again AFTER I made the address change which I assume is also recorded inside the NAS, probably in firmware.

I recalled that during the setup phase the WD Quick View software performs a 'discovery' of the NAS which is presumably recorded somewhere in the software. But what happens if the network is reconfigured or IP addresses changed AFTER the discovery phase? Does this introduce a complication for WD Quick View to overcome? Should I repeat the discovery phase after any network changes which will necessarily mean installing WD Quick View again?

I have now reinstalled WD Quick View and I assume it has picked up the new Static IP address. I had to make a corresponding changes to my router's configuration to support the use of a Static IP at the Ethernet port I have selected to attach the NAS.

Is this new reinstallation responsible for the improvement in the wireless performance? My Airport Extreme was previously maxing out at around 2.4MBps but this has now jumped to around 3.0 - 3.2MBps, a useful increase when transferring large files across a network. 

[philharve]

UPDATE

I seem to have gained a slight improvement in backing up performance (25%) as a result of resolving my IP addressing issue. Even my Airport Extreme can now manage almost 3.2MBps. Once again, the drag-copying of files between my MBP and the NAS are commendably fast and accurate. I have no complaints in this area. However, using Time Machine for backing up is still a nonstarter.

I am currently looking at other applications which might impact upon TM operation, for example, my Intego virus software.

I will followup any suggestions I receive from WD Support.

[philharve]

UPDATE

I have discovered a link between TM backups to network storage devices AND virus checkers. I use Intego's Internet Security Suite (VirusBarrier X6) and it seems it can interfere with the backing up process. I am in discussion with Intego Support to ascertain the magnitude of the problem, if one exists, and whether it can be overcome.