[michaeleggleton]

Hi guys.

I currently have 2x 1tb HDs in Raid 0 as my working drives, with the standard 320GB hd as boot etc. I use it predominately for final cut pro. I purchased a 2tb external drive (actually 2x 1tb in raid 0 as well) which connects eSata/FW800 etc.) Is time machine the best to use for this? Also worried about peformance/using up too much space on my external HD having copies. I dont need to have minute changes backed up every hour - end of the day would suffice.. but you dont get that option in timemachine. what are people's thoughts about the best way to setup this workflow??

thanks.

Michael.

[Simon]

If you turn on your external backup drive before you leave in the evening and turn it back off when you come in in the morning TM will only back up changes at the end of the day.

[CharlesS]

You could also leave Time Machine turned off and just update the backup manually at the end of each workday.

But I've gotta say - RAID0 for a backup? That's just asking for trouble...

[OreoCookie]

Not a good idea. Time Machine doesn't work too well with video files (if you change 1 Byte, you need to back up the whole file again). I suggest you use Time Machine for non-video files/small files and another piece of software such as Synk for video backups. Do not clone your drives and think of them as a backup!

[Simon]

Originally Posted by CharlesS 

But I've gotta say - RAID0 for a backup? That's just asking for trouble...

Indeed. I thought I had read his backup was RAID1. RAID0 is not at all a good idea for a backup disk.

[SierraDragon]

But I've gotta say - RAID0 for a backup? That's just asking for trouble...

I thought I had read his backup was RAID1. RAID0 is not at all a good idea for a backup disk.

I disagree, RAID0 is excellent for daily backup for most single-user setups if the capacity of more than one drive is necessary. It is least cost per GB, simple and fast. And it is backup, therefore by definition the backup is backed up by the original, making the higher failure rate of RAID0 mostly irrelevant. Keep a spare drive available and recovery can be very fast. JBOD also works.

RAID1 is lousy for backup because it doubles cost just to put multiple backup copies in the same physical location. That is really dumb because fire and theft are important issues we are backing up for. Better to use regular drives or RAID0 or JBOD and have those redundant drives off site.

RAID1 is good for real-time backup of things like financial transactions (e.g. a bank) that demand real-time backup and have the underlying application software designed for such backup. For the work that most of us do real-time backup is (a) unnecessary and (b) problematic because it automatically backs up our errors, crashes, etc. Best IMO is a manual backup at whatever frequency the data justifies (usually daily).

For large setups (very few forumees have them) with lots of hard drives the more complex RAID arrays should be investigated on a case-by-case analysis.

-Allen Wicks

[OreoCookie]

A RAID is not a backup! A bank doesn't have a RAID1 to have a backup, they do have separate backups, but a RAID1 (in this instance) minimizes downtime. It's not a backup. Most cheap RAIDs are software RAIDs and thus very, very ill-suited for backup purposes: you lose the software config, you lose your backup.

[besson3c]

RAID is also not a backup because it preserves the precise state of your file system, including when it is corrupted.

[Simon]

Well maybe it's a good time to reiterate these simple facts.

RAID is redundancy (of the disk, not the data) and quick recovery. (And in this context we are definitely looking at RAID1, not RAID0.)

RAID is not versioning. That would be something like TM.

RAID is not a backup. Backups are ideally remote and file-based.

[Veltliner]

Originally Posted by OreoCookie 

Do not clone your drives and think of them as a backup![/b]

Do you mean this only in reference to Raid) (it's too vulnerable for back-ups, but enhanced at-work speed).

But cloning a drive to a regular external hard disk should qualify as a back-up, shouldn't it?

[besson3c]

Originally Posted by Veltliner 

Do you mean this only in reference to Raid) (it's too vulnerable for back-ups, but enhanced at-work speed).

But cloning a drive to a regular external hard disk should qualify as a back-up, shouldn't it?

No.

If you are doing a block by block clone (e.g. Unix dd), the integrity of your copy will be only as good as the integrity of your original. If you are doing a file copy, this is another story.

[OreoCookie]

Originally Posted by Veltliner 

Do you mean this only in reference to Raid) (it's too vulnerable for back-ups, but enhanced at-work speed).

But cloning a drive to a regular external hard disk should qualify as a back-up, shouldn't it?

No, it does not only apply to RAIDs, cloning in general breaks with the basic rules of backups: you cannot guarantee that you always have a working copy. If, for one reason or another, the cloning process fails (e. g. because your source is problematic or you have a drive failure in the middle of your backup), you [i]don't have a working backup copy anymore[/b]. Plus, they waste a lot of space and it is not very practical to have several different backups.

Nowadays, there are plenty of other methods to back up your system: I use a combination of Time Machine, Aperture Vaults, Mozy and Synk. Time Machine always ensures I have a recent working copy of my data. Restoring from Time Machine is just as fast as cloning back, but a lot, lot more flexible (I can restore from any arbitrary point in time in my backup history, for instance).

Cloning does have applications (setting up many computers in the same way, migrating from one harddrive to another, etc.), but they are not a good backup method. Especially if it is your only backup method.

All RAID levels with the obvious exception of RAID0 give you protection against harddrive failure as well as the ability to concatenate space of several harddrive (exception: RAID1). A RAID is not a backup strategy. (A software RAID0 is a horrible destination for backups, though.)

[Veltliner]

Huh, so far I did a clone of my hard drive once in a while, and then backed up files I changed selectively. (Truly takes a lot of space)

But many people clone their drives to an external hard drive. Is there no advantage in doing so?

I'm going now into read more about this issue-mode.

[michaeleggleton]

thanks all for your replies.

Yes I am using Raid 0 on my backup device as well as on my original data drives internally (not actually my choice, there aren't any external drives I have seen with 1x2TB drive, or at least in Australia without going NAS and $x000's). So remember, if this external drive was to fail, then thats ok. As long as both seperate RAID arrays(with HDs from different manufacturers) dont fail at the same time. I think i will plug it in at the end of the day and let time machine do its thing. I dont realy want it to make lots of copies - i dont need it. I dont think some people understand how Final Cut works with video - my understanding is that the video data is captured, and sits there in whole in the capture scratch and doesnt change. The files that change are the .FCP - final cut project files with in a basic explanation just contain the in/out points with all the the effects/transitions etc. So i wouldnt have thought the video files actually change, just the smaller FCP files. Plus final cut automatically saves versions of these files. Thanks all for your help. Please correct me if my understanding is flawed however

[OreoCookie]

Originally Posted by Veltliner 

Huh, so far I did a clone of my hard drive once in a while, and then backed up files I changed selectively. (Truly takes a lot of space)

But many people clone their drives to an external hard drive. Is there no advantage in doing so?

Some people claim that
(0) They can work off a cloned drive: this breaks with another rule of backups: don't ever, ever work with a backup.
(1) Cloning is simpler: hasn't been true in a long while, there have been quite a few apps that are no more complicated than CCC or SuperDuper. Especially since 10.5, this point is for all intents and purposes moot.
(2) Cloning is faster: my favorite cloning software uses xyz so it only has to copy the files that have changed, so it's faster! First of all, all (serious) backup software for many, many moons use similar mechanisms, after all, if they are incremental/differential, they have to detect these things.
(3) Restoring from a clone is faster: in most instances, you clone to an external drive (as you should!), so typically you use FireWire or USB to connect it to your Mac. The speed is always limited by the interface. This covers most of the people, I would reckon. So let's assume your interface is `fast enough' (eSATA, for instance). Then, in some instances, there may be a speed difference in restoring data. But it's not night and day, just think of the sheer data volume: if you have 1 TB to restore, it'll be a while, harddrives can copy data only so fast. If you assume something like 20 or 50 MB/s, then this means you'll lose one working day either way.


For a while, cloning software was the only `simple' way to backup your files on OS X. Software like Retrospect or Tivoli Storage Manager are `pro apps' with all the complexity involved, so CCC (which, if I remember correctly, was the first) stepped up to the challenge. The idea of cloning is very easy to grasp and thus has become popular. Meanwhile, way better alternatives have emerged (my personal favorite apart from Time Machine is Synk, but there are others).

The most difficult thing to grasp for some is that they may need to put in some effort to find a good storage solution (which includes a backup solution and crucially depends on the budget). But that's another story for another thread

[Veltliner]

Thanks, Oreo Cookie, for the tasty comments.