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Why I Don’t Rely on Time Machine

joeontech.net

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Re: Why I Don’t Rely on Time Machine

#31

Post by facepalm »

keithpeter wrote: post #26
facepalm wrote: post #7

I've had the same experience, TM backups were suddenly broken several times.

Did the backup drive perhaps become unplugged or fail to unmount cleanly? I've managed to do that to an external hard drive under Linux and had the drive labelled as read-only subsequently. Just wondering aloud...

There is a mounting problem with OS sometimes, too. I don't remember all the occasions, but I am very careful with ejecting the disk (at the moment OS X forces me to shutdown to "eject"). Still, I'd understand if the last backup would be broken that way, but why the whole disk? A backup shouldn't be that brittle.

Re: Why I Don’t Rely on Time Machine

#32

Post by pixl97 »

hga wrote: post #30
bboreham wrote: post #25

Earlier quoted context omitted.

> Current LTO-4 and LTO-5 tapes [...] go for $22-23, uncompressed capacities are 800 and 1.5 GB respectively. I think you meant 1.5TB. However, why not just use hard disk drives at just over twice that price? You'd get quite a lot of them for the cost of the tape drive.

Because tapes are much less fragile than hard disks, and I can stash a bunch of tapes in my safe deposit box and other places. As well as have many copies of my data as I keep monthly full backups for at least a year. And, hmmm, my tapes as I use them are more reliable than my Seagate enterprise disks, and that's with the latter not moving around (i.e. in all my post-mid-2011 tornado hardware, I've had two disk failu…

>Because tapes are much less fragile than hard disks,

In 'single serve server' configurations, such as small businesses, tapes work well because administrative rather than technical staff can replace the tapes daily reducing costs. If the tape is ejected then the user knows it safe to put the next tape in. If there is a failure the software itself can notify a systems administrator. With hard drives a non technical user has no idea if the disk is still mounted and live, leading to corruption issues if it is removed.

Re: Why I Don’t Rely on Time Machine

#33

Post by pixl97 »

joesmo wrote: post #29

I experience failures like this with Time Machine every couple of months. The only thing to do is wipe the previous backup and start anew. This happens on all my Macs so it's not device specific nor is it related to the underlying backup medium which is working perfectly. If you absolutely cannot take even the smallest chance of losing your data, TM is not a good choice. If you need something that runs for years on e…

Why are the operating system supplied backups so terrible when there are really good examples to build from?

That said, in Windows 8+ the file history (not a full system backup, but a user data backup) seems to work well enough at keeping history and not filling up the backup drive. In general taking one system image from the original install gets you back up and running well enough.

Re: Why I Don’t Rely on Time Machine

#34

Post by hga »

pixl97 wrote: post #32
hga wrote: post #30

Earlier quoted context omitted.

Because tapes are much less fragile than hard disks, and I can stash a bunch of tapes in my safe deposit box and other places. As well as have many copies of my data as I keep monthly full backups for at least a year. And, hmmm, my tapes as I use them are more reliable than my Seagate enterprise disks, and that's with the latter not moving around (i.e. in all my post-mid-2011 tornado hardware, I've had two disk failu…

>Because tapes are much less fragile than hard disks, In 'single serve server' configurations, such as small businesses, tapes work well because administrative rather than technical staff can replace the tapes daily reducing costs. If the tape is ejected then the user knows it safe to put the next tape in. If there is a failure the software itself can notify a systems administrator. With hard drives a non technical u…

And even more fragile if still spinning ... yeah, it would never occur to me to have anyone but trusted technical staff physically swapping hard disks around. Whereas I think people, at least us older types who used VHS tapes especially, have an idea for how tough/fragile computer backup tapes are (maybe a little tougher than a VHS tape, but not enough to make a difference in how you handle it).

(We'll ignore for the moment that I never trusted anyone but myself to run the backup system and mount and unmount tapes, with one exception. :-)

Re: Why I Don’t Rely on Time Machine

#35

Post by kitsunesoba »

Has the state of ZFS on OS X improved at all? It seems like the ideal filesystem for backups, but last I checked there were major issues with using ZFS-formatted external drives — enough so that the developers working on the project recommended against it.

If it hasn’t I might put together a cheap FreeBSD box for the express purpose of networked file storage and backup.

Re: Why I Don’t Rely on Time Machine

#37

Post by ioquatix »

rcthompson wrote: post #23
ioquatix wrote: post #14

Earlier quoted context omitted.

Deleting the old backup is no longer the first step AFAIK. Yes, I have seen that behaviour in the past. Now, it gets renamed and then deleted once the next backup is completed successfully.

Still, it sucks that the solution involves losing your entire backup history.

Yes, it's completely rubbish, I agree. I'm pretty sure the people who are working on Time Machine are aware of this problem and I'm pretty sure it stems from the unreliability of mounting disk images over a network. Quite possibly due to hardware issues (e.g. flakey AirPort/Time Capsules) or problems with HFS+ filesystem. At a guess, I'd say they had to do their best to work around these issues. There is no excuse though, especially when it comes to backup.

Re: Why I Don’t Rely on Time Machine

#38

Post by ketralnis »

coldtea wrote: post #24

> Huh. The Time Machine preference pane suggested that I try again later, and I did, with the same result. Since there was an error creating a folder, I guessed that the disk might have some errors, so I ran Disk Utility. Sure enough, there were errors, but Disk Utility couldn’t fix them. Neither could DiskWarrior. Or TechTool Pro. So I was left with no choice but to reformat the disk and start over from scratch. I s…

For unrecoverable corruption and no hardware failures you don't need bugs in 3 pieces of reading software. You just need one bug in the writing software. Or a momentary hardware issue like a power surge or lost power during a write in such a way that the journaling can't fix

Re: Why I Don’t Rely on Time Machine

#39

Post by coldtea »

ketralnis wrote: post #38
coldtea wrote: post #24

> Huh. The Time Machine preference pane suggested that I try again later, and I did, with the same result. Since there was an error creating a folder, I guessed that the disk might have some errors, so I ran Disk Utility. Sure enough, there were errors, but Disk Utility couldn’t fix them. Neither could DiskWarrior. Or TechTool Pro. So I was left with no choice but to reformat the disk and start over from scratch. I s…

For unrecoverable corruption and no hardware failures you don't need bugs in 3 pieces of reading software. You just need one bug in the writing software. Or a momentary hardware issue like a power surge or lost power during a write in such a way that the journaling can't fix

That's the thing though: it could be hardware failure (or software failure unrelated to TM, like the power surge/writing glitch that journaling can't fix etc).

He just says there were errors on the disk and that 3 disk utils couldn't fix them. Nothing of that translates to that the error was TM's fault, so it makes no sense blaming it.

If the disk had issues, they would have also affected any other backup software.

Re: Why I Don’t Rely on Time Machine

#40

Post by projct »

kitsunesoba wrote: post #35

Has the state of ZFS on OS X improved at all? It seems like the ideal filesystem for backups, but last I checked there were major issues with using ZFS-formatted external drives — enough so that the developers working on the project recommended against it. If it hasn’t I might put together a cheap FreeBSD box for the express purpose of networked file storage and backup.

It hasn't as far as I'm aware but here's the project page: https://openzfsonosx.org

I just did the cheap FreeBSD box thing with FreeNAS and a lenovo server I picked up on Amazon, works great

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