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#30813 - 08/14/14 03:15 PM Wipe Time Machine Drive and Start Over?
slolerner Offline


Registered: 08/25/09
Loc: New York City
Well, my Time Machine drive is pretty weird by now, three internal computer drives later. It is not backing up on schedule, etc. So before I just do a zero-out and start over now that my computer is cleaned up, (appears to have been some corruption in an email archive) I'm going to ask Ganbustein what to do BEFORE I screw things up instead of afterward.. or in addition to... tongue


Edited by slolerner (08/14/14 03:16 PM)
Edit Reason: clarity
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#30822 - 08/15/14 03:40 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
ganbustein Offline


Registered: 08/04/09
Sorry, not enough information.

The first thing I'd do is find out why Time Machine is not backing up on schedule. I fail to see how a corrupted email archive could have any effect on TM. Not understanding the problem makes any proposed solution uncertain.

If your problems stem from failing hard drives (as suggested by the number of them you've gone through), it's possible your backup is garbage. Many many years ago, I needed to wipe my primary boot drive and start over. Before doing that, I made three separate clones. It turns out all three of them were bad. In the aftermath, I figured out the root problem (and the reason I had been having random crashes) was that I was getting occasional and undetected read errors from the primary drive. (All drives were attached over SCSI to a Mac Plus. Like I said, this was many years ago.) When making the clone, the software I was using (Retrospect) would read a chunk of data from the primary, write it to the clone, and then read it back from the clone to ensure it had been written correctly. The flaw was not realizing that what had been read was occasionally garbage, and double-checking that that garbage had been faithfully copied wasn't helpful.

SCSI is ancient history. I don't know that modern drives over modern busses (FireWire, USB, even WiFi) have the same problem that sometimes what you get from the drive is not what the drive sent down the bus. I merely mention the possibility that backing up a failing drive may mean you've backed up garbage. In that case, there's no point keeping the backup around.

But I don't know. Not enough information. Not knowing why you've been having problems makes it impossible to tell you how to proceed. I also don't know what it would cost you to lose your backup. A cost/benefit analysis is dependent on knowing both the costs and the benefits of each of your options. I know none of those.


I see from your signature that you're still running 10.6.8. If it's at all feasible, you really should consider upgrading to a current OS. The only thing it'll cost you is compatibility with ancient software (primarily any PowerPC-only apps, which perforce have not been updated since 2006, eight years ago), and the one week tops that it will take you to retrain your muscle memory to use natural scrolling. (Natural scrolling feels weird at first, but Apple was right. It really is the correct way to scroll.)

But one thing at a time. Get your computer working, then upgrade.

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#30824 - 08/16/14 06:19 AM Re: Wipe Time Machine Drive and Start Over? [Re: ganbustein]
Ira L Offline


Registered: 08/13/09
Loc: California
Originally Posted By: ganbustein
and the one week tops that it will take you to retrain your muscle memory to use natural scrolling. (Natural scrolling feels weird at first, but Apple was right. It really is the correct way to scroll.)


And if old habits die hard, there is an option to go back to "old" scrolling. laugh
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On a Mac since 1984.
Currently: 27" iMacs, Macbook Air, macOS 10.14.x,; iPhones, iPods and iPads galore!

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#30828 - 08/16/14 08:34 AM Re: Wipe Time Machine Drive and Start Over? [Re: Ira L]
slolerner Offline


Registered: 08/25/09
Loc: New York City
The Time Machine Preferences Panel tells me it is set to make a back-up the following hour, but when I enter TM, there is only one backup for every day unless I prompted "Back up now." This is the third drive that has been backed up onto that drive, each creating a new folder, that is when we were discussing holding down option when entering TM to be able to see the backups for the older drives. Then, there was the dumb problem where I tried to delete a backup and it got stuck in the trash and I had to go into the treacherous Terminal. I don't know if it had anything to do with this, but later on I noticed the backups of the oldest drive only contains the user folder, which is good to have, but the rest is gone.

Now that it seems I have resolved the haunting problem in the "Weird Assorted Problems???" string:

http://www.finetunedmac.com/forums/ubbthreads.php?ubb=showflat&Number=30454#Post30454

I feel like it may be time to just wipe the TM drive and start over like I did when I couldn't resolve the problem with the internal drive and it was the only solution I could come up with. I don't know if TM kinda starts a new file (not folder) when you wipe a drive and start over because there are so many changes trying to figure them out would be 'nuts.' Just kind of start fresh without artifacts of anything. Really can't imagine a case scenario where something probably corrupt from years ago is worth keeping or fixing. What say you?
_________________________
Mid 2010 MacBook Pro 13"
2.4GHz, 750GB SATA HD, 8 GB RAM, OS 10.7.5
1 HDX1500 2TB Ext.HD, 2 HDX1500 1TB Ext.HD
HP Laserjet 6MP printing postscript via 10/100 Intel print server
Netgear WN2500RP Range Extender (Ira rocks!)
Linksys WRT1900AC Wireless Router
Brother MFC-9340CDW Color Laser
iPad Air

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#30831 - 08/16/14 11:14 AM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
artie505 Online


Registered: 08/04/09
> Really can't imagine a case scenario where something probably corrupt from years ago is worth keeping or fixing. What say you?

Would you lose anything critical if you wiped the drive?

I don't see the point in maintaining a backup that's not only unnecessary, but possibly corrupt.

That said, I'll say that keeping a backup of your home folder under any circumstances would probably be a good idea.
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#30835 - 08/16/14 04:55 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
ganbustein Offline


Registered: 08/04/09
Originally Posted By: slolerner
The Time Machine Preferences Panel tells me it is set to make a back-up the following hour, but when I enter TM, there is only one backup for every day unless I prompted "Back up now."

What are your sleep settings? Time Machine will not back up while your computer is asleep (or off). (If it missed a backup because it was asleep, it will start one two minutes after you wake it up. If it was turned off, it won't start making automatic backups until one hour after you turn it back on. If you never leave it on for a whole hour, it'll never back up except manually.)

When Time Machine was new, there were a lot of hacks in circulation to let people "tune" TM. Some people were so sure that hourly backups were surely a bad idea that they insisted on finding some way to make TM back up only daily or even less often. Is it possible you ran one of these at some time in the past?

One quick check is to run the following command in Terminal:

Code:
defaults read /System/Library/LaunchDaemons/com.apple.backupd-auto | grep Interval


Depending on your OS version, the output should be either:
StartInterval = 3600
or
Interval = 3600
(preceded by a bunch of spaces). If it's any number other than 3600, somebody has messed with the frequency of automatic backups.

Originally Posted By: slolerner
later on I noticed the backups of the oldest drive only contains the user folder, which is good to have, but the rest is gone.

When TM was new, Apple gave users easy access to an option to not back up system files. That option was a mistake, and Apple removed it in later versions. You really do want to back up your system files. Otherwise, you cannot meaningfully do a full-disk restore. System files rarely change, so even though they're big in aggregate, they don't take up as much of your precious backup disk space as one might naively fear.

You probably had that option on in the beginning, and then turned it off. The default (and correct) option is to back up system files.

Originally Posted By: slolerner
I feel like it may be time to just wipe the TM drive and start over like I did when I couldn't resolve the problem with the internal drive and it was the only solution I could come up with. I don't know if TM kinda starts a new file (not folder) when you wipe a drive and start over because there are so many changes trying to figure them out would be 'nuts.' Just kind of start fresh without artifacts of anything. Really can't imagine a case scenario where something probably corrupt from years ago is worth keeping or fixing. What say you?

Yes, when you wipe a drive, TM sees it as a brand new drive and starts a new backup for it. (On OS X 10.7 Lion and later, there is a Terminal command to tell it to adopt a new drive as a reincarnation of a previously backed up drive, but you have to do that manually. There was a very complicated procedure, not for the faint of heart, to accomplish the same thing in OS X 10.5 Leopard. You cannot do it at all in OS X 10.6 Snow Leopard.)

It's sounding more and more like what you want to do is start TM fresh on a newly-erased drive. Either buy a new drive, or erase the existing one. It doesn't sound like you'll be losing anything important if you do the latter. Do not waste time trying to futz around and trash just some of it. Erase the whole drive. (If you start with a new drive, don't forget to set the partitioning scheme to GUID.)

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#30840 - 08/17/14 04:43 PM Re: Wipe Time Machine Drive and Start Over? [Re: ganbustein]
slolerner Offline


Registered: 08/25/09
Loc: New York City
Thank you, Ganbustein. I did not do any mods or use special settings for Time Machine, so I think the issue of having only the user folder on the older backups is corruption.

I would like to reformat the other externals I have and then put the files back on them. How I propose to proceed is to turn off Time Machine and restart the computer so it does not see it as a Time Machine Drive? and then since there is still almost a Terrabyte of free space on it, I want to move a few of my Silverlining backups onto there from the 1 TB drive they are on for storage, erase THAT drive and reformat it, then move those backups onto the freshly formatted 1 TB. That was the drive that would not eject when I was having all the "weird assorted problems." I want to make sure it's clean. Once that drive is zeroed out and reformatted, I will move the Silverlining backups back onto the drive where they were and zero out the Time Machine Drive completely. I want to take the opportunity of having space to clean the other drive, but not wipe out my Time Machine backups until I feel confident the Silverlining backups are solid. What do you think?
_________________________
Mid 2010 MacBook Pro 13"
2.4GHz, 750GB SATA HD, 8 GB RAM, OS 10.7.5
1 HDX1500 2TB Ext.HD, 2 HDX1500 1TB Ext.HD
HP Laserjet 6MP printing postscript via 10/100 Intel print server
Netgear WN2500RP Range Extender (Ira rocks!)
Linksys WRT1900AC Wireless Router
Brother MFC-9340CDW Color Laser
iPad Air

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#30842 - 08/17/14 05:31 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
ganbustein Offline


Registered: 08/04/09
Sounds good.

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#30843 - 08/17/14 05:57 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
artie505 Online


Registered: 08/04/09
I'll make one suggestion: Before you zero out any drives, run surface scans on them.

Zeroing out a drive will "correct" bad blocks by writing them out of the equation, but will not tell you that it's doing so, and knowing that a drive has/had bad blocks is important...possibly critical info.
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#30844 - 08/17/14 06:13 PM Re: Wipe Time Machine Drive and Start Over? [Re: artie505]
slolerner Offline


Registered: 08/25/09
Loc: New York City
What would you use to do a surface scan? (Why not just zero out and let bad blocks be written out?)

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#30845 - 08/17/14 07:09 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
artie505 Online


Registered: 08/04/09
Originally Posted By: slolerner
What would you use to do a surface scan? (Why not just zero out and let bad blocks be written out?)

An HDD may come from the factory with bad blocks, which is not a disaster, but its developing new ones during the course of its use is a "sit up and take notice" danger sign*.

Therefore, my approach to drives is to run a surface scan immediately upon acquiring them (I'd follow up the discovery of any factory-issue bad blocks with a zero run, but I've never found any.), and to follow it up with subsequent scans, although on no particular schedule, to see if any new bad blocks have developed.

I suspect that you've never run scans on your drives, so you won't know whether any bad blocks you may find are factory-issue or newly developed, but knowing that they're there and zeroing them will give you both a fresh start and the knowledge that you ought to keep close tabs on the affected drive.

You can run a surface scan from within OS X via Terminal (I'll walk you through it if you'd like.), but there are any number of 3rd party utilities that can do the job more easily. TechTool Deluxe, which shipped with all Macs at one time, is a likely candidate if it will run on your current deuced Mac(hina), but TechTool Pro and others of its ilk (but not DiskWarrior) can also do the job.

Edit: * See this post by joemikeb.


Edited by artie505 (08/18/14 10:21 AM)
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#30847 - 08/18/14 01:46 PM Re: Wipe Time Machine Drive and Start Over? [Re: artie505]
joemikeb Offline

Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
To add to Artie's comment, according to a study of hard drive failures run by Google Labs, NEW bad data blocks on a drive are the single best indicator of impending drive failure within the next 60 days. Because of the threshold set by the drive manufacturers, S.M.A.R.T. values are virtually useless to indicate anything other than the drive has already failed.

Unfortunately, there are no effective free or cheap tools available that will perform a surface scan. Checkmate performs periodic routine surface scans of internal and attached HDDs and SSDs and is the least expensive I have found. TechTool Pro or Drive Genius will perform a surface scan on demand. None of these will work on a network drive. frown
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#30849 - 08/18/14 07:18 PM Re: Wipe Time Machine Drive and Start Over? [Re: artie505]
artie505 Online


Registered: 08/04/09
Correction: TechTool Deluxe did not ship with any Macs, rather it shipped with AppleCare if you purchased it.

I just tested my v 3.1.3 disc, and the TTD app runs fine on my April 2010 15" MacBook Pro, so I assume that it'll work on your Mac if you've got it.
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#31376 - 10/01/14 06:17 PM Re: Wipe Time Machine Drive and Start Over? [Re: artie505]
slolerner Offline


Registered: 08/25/09
Loc: New York City
Zeroed out the 2TB TM drive, moved files from the two 1TB backups off those drives to the 2TB. Zero'ed out those drives, and then moved their previous content back. Zero'ed out 2TB TM drive again and began a new TM drive starting today. No issues, so far, so good. I feel like all my backup drives took a shower and are clean.

Thanks for everyone's input and advance warnings to avoid problems.

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#31381 - 10/02/14 03:45 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
joemikeb Offline

Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Glad things are up and running again. Micromat, the vendor of TechTool Pro, has a new product on the market called Checkmate. It runs in background at various times of the day and performs a variety of tests on your drives including S.M.A.R.T., memory, I/O, Power On Self Test, Surface Scans, Partition Maps, Volume structures, and File Structures on all attached volumes. It does not do any repairs but it will alert you to potential or actual drive failures.

DISCLAIMER: I have no pecuniary relationship with Micromat other that that of a customer for their products.
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#31383 - 10/02/14 04:09 PM Re: Wipe Time Machine Drive and Start Over? [Re: joemikeb]
slolerner Offline


Registered: 08/25/09
Loc: New York City
Sounds good. Would have saved me a lot of trouble to know 100% at the beginning of all the mess I had to clean up that the internal drive REALLY was on its way out. I think Micromat used to (is) on FTM?
_________________________
Mid 2010 MacBook Pro 13"
2.4GHz, 750GB SATA HD, 8 GB RAM, OS 10.7.5
1 HDX1500 2TB Ext.HD, 2 HDX1500 1TB Ext.HD
HP Laserjet 6MP printing postscript via 10/100 Intel print server
Netgear WN2500RP Range Extender (Ira rocks!)
Linksys WRT1900AC Wireless Router
Brother MFC-9340CDW Color Laser
iPad Air

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#31386 - 10/02/14 05:15 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
joemikeb Offline

Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: slolerner
I think Micromat used to (is) on FTM?

It has been a while since Micromat Tech 3 checked in here but your memory serves you well
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joemikeb • moderator

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#31448 - 10/07/14 10:06 AM Re: Wipe Time Machine Drive and Start Over? [Re: joemikeb]
slolerner Offline


Registered: 08/25/09
Loc: New York City
I read a little and TechTool Pro and Checkmate seem kind of hard to tell apart?
_________________________
Mid 2010 MacBook Pro 13"
2.4GHz, 750GB SATA HD, 8 GB RAM, OS 10.7.5
1 HDX1500 2TB Ext.HD, 2 HDX1500 1TB Ext.HD
HP Laserjet 6MP printing postscript via 10/100 Intel print server
Netgear WN2500RP Range Extender (Ira rocks!)
Linksys WRT1900AC Wireless Router
Brother MFC-9340CDW Color Laser
iPad Air

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#31454 - 10/07/14 02:17 PM Re: Wipe Time Machine Drive and Start Over? [Re: slolerner]
joemikeb Offline

Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: slolerner
I read a little and TechTool Pro and Checkmate seem kind of hard to tell apart?

Checkmate is cheaper, runs autonomously in background, and is not capable of making repairs.
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