Time Machine Failure

[bayswater]

Early this morning I got this message:

"Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you. Click Start New Backup to create a new backup. This will remove your existing backup history. Click "Backup Later" to be reminded tomorrow."

Looking this up, I found that backups (I had year's worth) are often no longer accessible because the large backup file has become corrupt. The error is documented in Apple Support with a summary here http://pondini.org/TM/C13.html

The lesson is that no matter how convenient TM might seem I also need periodic backups using other utilities (SuperDuper in my case)

[mikehalloran]

Early this morning I got this message:

"Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you. Click Start New Backup to create a new backup. This will remove your existing backup history. Click "Backup Later" to be reminded tomorrow."

Looking this up, I found that backups (I had year's worth) are often no longer accessible because the large backup file has become corrupt. The error is documented in Apple Support with a summary here http://pondini.org/TM/C13.html

The lesson is that no matter how convenient TM might seem I also need periodic backups using other utilities (SuperDuper in my case)

So, you are saying that a new backup using SD is more reliable than a new backup using TM? That's not the conclusion I draw.

Check the SMART status of the drive you are using for TM. I have encountered this three times - each time, the drive was in the process of failing (I take care of over 30 Macs). If the drive is in a Time Capsule, you have to pull it out and connect it directly (usb dock or housing etc) to check. Although TechTool gives you a readout of 18 parameters when running a SMART check, Disk Utility will pop up red warning messages to back up your files immediately and replace the drive.

Many of us use an external dock and swap drives for redundant backups - TM is very good for that. In 10.8, you are supposed to be able to automate this but I haven't tested it, yet.

[MIDI Life Crisis]

Regardless of your backup method, it should always include multiple backups. Backups of the backups, if you will. Even if you won't.

[bayswater]

So, you are saying that a new backup using SD is more reliable than a new backup using TM?

No Mike, I'm saying having two backups is better than one. I got into a bad habit of relying solely on TM because it requires no attention once it is set up. If you read the articles I linked to, you'll see the view that corruption of TM backups happens, and that Apple has not figured out a consistent cause. One suggestion is that some filenames might give TM problems. In my case it might have been overheating of the drive, but there could be any number of reasons, and corruption is one of them.

As you suggested, ML will be able to do backups to more than one drive and that will improve the odds. But if you consider that different backup algorithms might make different types of errors, you'd be better off using more than one application if you make multiple backups.

[cuttime]

Isn't there supposed to be a way to verify TM backups in one of the OSX versions? (<opt click> the TM icon)? Did this give you any warning?

Using <opt click> in my machine in 10.6.8 gives a "verify" option, but I think all it really does is just perform another backup.

[bayswater]

Apparently TM performs verifications on its own. That's what happened in my case. The verification failed and the backup volume was locked when the test failed.

[sjared]

I am not really sure with what the deal is but I have been using Time Machine for the longest time and lucky me, I have never encountered any form of problem with it. I am guessing that there could be an issue with how you are going to make the things work just like that. True enough, there would not be much issue with the reliability factor but I suppose you should take a deeper look into it.

[zed]

Sorry that you had to face this Bayswater, but glad that you didn't actually lose any data.

I am not really sure with what the deal is but I have been using Time Machine for the longest time and lucky me, I have never encountered any form of problem with it.

You are lucky indeed. I have lost a Time Machine backup to corruption. Fortunately it was only a backup and I didn't lose any valuable files either. But it was certainly inconvenient and necessitated the purchase of a new drive.

Some of my drives are almost full, so I'll need to buy a couple of new ones this month and swap out some of my internals (the Samples drive especially). The current Samples drive will become a backup of that drive, and will preferably be stored off-site.

[bayswater]

Sorry that you had to face this Bayswater, but glad that you didn't actually lose any data.

I was lulled into a false sense of security after almost a year of clean backups. But no more! It's back to a more disciplined approach.

I need some new drives for backup too. Are you getting the locally (e.g. NCIX)?

[zed]

I need some new drives for backup too. Are you getting the locally (e.g. NCIX)?

I usually go to Atic, but then again, I tend to price check both before deciding which.

I'm thinking of getting a couple of 3TB drives, though I am a bit concerned that the drives may be more likely to fail with such high capacities.

[bayswater]

I'm thinking of getting a couple of 3TB drives, though I am a bit concerned that the drives may be more likely to fail with such high capacities.

I had the same concern. Also the price point for the "obsolete" 2T might be better.