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camner 04-02-2004 12:48 AM

unclear about some usage issues
 
Pardon me if these are obvious, but I was not clear about them after reading the help stuff...

1. The help talks about using SD to create "checkpoints". Do I presume correctly that the way to do this is to get SD to create a complete image of my main drive whenever I want to create a checkpoint from which I could restore whenever I wish?

2. I have a second internal drive I use for a daily backup of important folders (Documents, Desktop), but I start with a clone so I can boot from it if needed. Can I use SD for this daily partial backup? If so, I presume I have to write a custom script, right? Can that custom script be set for a "smart" backup? But see #5 for confusion about the suitability of this.

3. The docs indicate that an image backup is the "best" backup (vs a folder backup). Does that suggest that folder backups are most suitable for moving systems around, and that otherwise they aren't so useful?

4. Why isn't there a way (or is there) to create an image without actually creating a clone first? Wouldn't that be an effective way of creating "checkpoints" without having to create a folder by folder clone at the same time?

5. The help files state: "Do not use Smart Update to selectively copy files to or from a clone:" This confuses me. What is the point of Smart Update if it isn't to selectivey copy files from one's main drive to a backup drive (internal or external) that one first created via the cloning process?

Thanks...

dnanian 04-02-2004 08:11 AM

Thanks for the post, camner. I'll do my best to answer each question in turn.

Quote:

Originally Posted by camner
1. The help talks about using SD to create "checkpoints". Do I presume correctly that the way to do this is to get SD to create a complete image of my main drive whenever I want to create a checkpoint from which I could restore whenever I wish?

By "checkpoint", in general, we mean the base volume of a safety clone. When you create a safety clone, you've basically "locked down" the original system, checkpointing it as it is at the time of the safety clone. When you boot from the Sandbox, you can modify the system on it to your heart's content, without affecting the system on the original.

If the sandbox proves unstable after these modifications, you can reboot from the original checkpoint, and your system will be as it was.

The Safety Clone is not a "complete" image, as it shares a number of components with the original, including (depending on the script you select) Applications and your personal data files. It's not really something you "restore", as such -- you boot back to the original when you need to "roll back".

At that point, you can "fix" the Safety Clone by re-running the original script with Smart Update.

Quote:

Originally Posted by camner
2. I have a second internal drive I use for a daily backup of important folders (Documents, Desktop), but I start with a clone so I can boot from it if needed. Can I use SD for this daily partial backup? If so, I presume I have to write a custom script, right? Can that custom script be set for a "smart" backup? But see #5 for confusion about the suitability of this.

The whole idea of the "Smart Update" is that the partial update is handled automatically: only the changed files get copied over. You don't really have to make a custom script -- SuperDuper will evaluate the files (very quickly) and only copy the changes.

Quote:

Originally Posted by camner
3. The docs indicate that an image backup is the "best" backup (vs a folder backup). Does that suggest that folder backups are most suitable for moving systems around, and that otherwise they aren't so useful?

It does? Can you point me to where I said that, because that's not what I meant to say!

What I meant to say was that a Safety Clone doesn't substitute for a regular backup -- which you can do, as indicated, with SuperDuper!, depending on your individual requirements.

Quote:

Originally Posted by camner
4. Why isn't there a way (or is there) to create an image without actually creating a clone first? Wouldn't that be an effective way of creating "checkpoints" without having to create a folder by folder clone at the same time?

I'm not quite sure what you mean: perhaps we're using different terminology. An "image" is a clone -- typically, in the documentation, when I refer to an "image" I mean a DMG. You can store a clone in a DMG or on another drive.

Quote:

Originally Posted by camner
5. The help files state: "Do not use Smart Update to selectively copy files to or from a clone:" This confuses me. What is the point of Smart Update if it isn't to selectivey copy files from one's main drive to a backup drive (internal or external) that one first created via the cloning process?

I had hoped to make that clear, and -- clearly -- I failed. What I was basically trying to say was that Smart Update itself will be selective about what it copies. You shouldn't "cut down" the folders it examines, because -- as described -- the "result" will be the same as an "Erase, then copy". In other words, if you tell it to just copy "/Documents" (as opposed to letting it figure it out for itself), it'll delete anything on the destination that's outside the specified folder ("/Documents"), because that's what you'd get with an Erase, then copy.

Instead, just use your regular script, and if things outside /Documents haven't changed, Smart Update'll figure it out, and won't copy them.

Hope that helps!

camner 04-02-2004 01:18 PM

Thank you for your prompt and complete reply.

1. I now understand better what you mean by checkpoint. I think where I was confused is that a "checkpoint" to me implied the ability to have multiple checkpoints (as in XP's "system restore"). You didn't actually say that (or even imply it). I just inferred it. What I now understand is that Sandbox is a single checkpoint...it can be updated at any time by a recloning process. It allows one to...safely...make changes to one's system, and if the changes work well, one can create a new checkpoint.

2. I haven't tried this yet, but working with other backup utilities (SilverKeeper, for example), it takes a while to actually do the smart backup, so I set it to only copy changes to my Documents folder. I now understand that the way SD works, this would be a mistake!

3. You write, on page 16 "...restoring one of these images is much, much, faster than doing a 'file by file' copy". Once again, I inferred something you didn't really say. I concluded that by creating multiple dmg images, I would accomplish two things: (1) multiple "checkpoints", and (2) quick restores (as opposed to "cloning back" from my backup drive). It still isn't clear to me what you would recommend as a backup strategy for someone who has a second internal drive whose sole purpose is backup...should I also keep periodic dmg images, or be content with regular smart updates to the 2nd internal drive.

4. My idiocy here. I just didn't read the docs carefully enough. I now understand that I can select an image as the target of a cloning...I had overlooked that and thought the only way I could create a dmg image was by checking the box while doing a file-by-file cloning.

5. Here I think you are not being clear enough in the docs. Until I read your reply, I did not fully understand the implications of doing a Smart Update with a 'cut down' list of files. The implications are sufficiently staggering (destruction of clone!) that I might suggest that when someone attempts to do so (assuming you can detect it), a nice window saying something to the effect of "hey, are you absolutely sure you want to do this--you will lose all files on the target that are not contained in the folders you specified" would be a great feature.

Another question...can one schedule a SD cloning as a cron job?

dnanian 04-02-2004 05:19 PM

Quote:

Originally Posted by camner
2. I haven't tried this yet, but working with other backup utilities (SilverKeeper, for example), it takes a while to actually do the smart backup, so I set it to only copy changes to my Documents folder. I now understand that the way SD works, this would be a mistake!

Indeed: it doesn't take much time to evaluate the whole drive, and it would, indeed, be a mistake.

Quote:

Originally Posted by camner
3. You write, on page 16 "...restoring one of these images is much, much, faster than doing a 'file by file' copy". Once again, I inferred something you didn't really say. I concluded that by creating multiple dmg images, I would accomplish two things: (1) multiple "checkpoints", and (2) quick restores (as opposed to "cloning back" from my backup drive). It still isn't clear to me what you would recommend as a backup strategy for someone who has a second internal drive whose sole purpose is backup...should I also keep periodic dmg images, or be content with regular smart updates to the 2nd internal drive.

It all really depends what you want to do the backups for, and whether you want multiple versions saved. For most people, that's overkill, so I'd recommend running from a Safety Clone, and keeping a full, smart-updated backup of the source drive (which contains the user files: there's no real reason to back up the Sandbox).

If you want to have multiple rollback points, I'd probably recommend creating a few DMG images on a drive large enough to hold them. Each should be a growable sparseimage, named -- for example -- Monday, Wednesday and Friday.

To update Monday's, you'd mount it on Monday and Smart Update to it. Same for Wednesday. This'd give you three rollback points, but note that none of them would be bootable (though restores from them should be).

Quote:

Originally Posted by camner
5. Here I think you are not being clear enough in the docs. Until I read your reply, I did not fully understand the implications of doing a Smart Update with a 'cut down' list of files. The implications are sufficiently staggering (destruction of clone!) that I might suggest that when someone attempts to do so (assuming you can detect it), a nice window saying something to the effect of "hey, are you absolutely sure you want to do this--you will lose all files on the target that are not contained in the folders you specified" would be a great feature.

Well, I'm not sure how much more I can say. I point out the issue on page 10:
Do not use Smart Update to selectively copy files to or from a clone: you’ll end up with the same result as if you had selected Erase, then copy, which probably isn’t what you want. For more information, see the discussion of Smart Update on page 14.
and then again on page 14:
Important Note
As we said above, the result of a Smart Update will be exactly what you’d get if you chose Erase Sandbox, then copy files from Macintosh HD. That means that any files “outside” the set of files selected by the copy script will be erased.
For example, let’s say you did an initial copy using Backup – all files. Then, later, you decided to try to only “update” your user files the Backup – user files script.
Remember that the result of a Smart Update will be exactly what you’d get if you chose Erase Sandbox, then copy files from Macintosh HD with the same script. That means that all files on Sandbox other than the ones selected by Backup – user files will be deleted!
Instead, you should choose the same script you used previously: Backup – all files. SuperDuper will automatically skip any files that didn’t change, so you’ll end up copying the smallest amount of data possible to make Sandbox match Macintosh HD again.
Where else would you like to see a similar warning? It's hard to put it in the UI, because the fact is that people don't read warnings... unfortunate, but true.

Quote:

Originally Posted by camner
Another question...can one schedule a SD cloning as a cron job?

Not at present, no.

camner 04-02-2004 08:34 PM

Aha, I think I have it. The phrase "Do not use Smart Update to selectively copy files to or from a clone" hinges on the word 'selective'. My initial reaction was "Hmmm, that's strange; the very nature of a Smart Update is that only SOME files are copied. Since Smart Update only copies some files, the key point here must be not to use Smart Update with a clone, which is weird." In other words, I didn't understand.

How about: "When the target is a cloned disk, only use Smart Update if the source is an entire volume. You’ll end up with the same result as if you had selected Erase, then copy, which probably isn’t what you want, because you'll get a copy only of the files specified in the source, which will effectively result in the destruction of your clone".

Thanks for helping me understand all this.

dnanian 04-02-2004 10:17 PM

Well, actually, while that's technically true, it's not quite what I'm trying to get at.

The basic deal is that if there are files on the target that you want to keep, and you're not "selecting" them for copy from the source, they're going to get deleted.

So, if you've created a given clone -- full or not -- with a given script, you should typically use the same script to Smart Update it.

In both cases, the effective result is as if you had chosen "Erase, then copy", which is why I kept trying to emphasize that: nothing on the target, other than those files that would normally get copied from the source, will be present on the target when you're done.

I'll try to rework this part of the manual for the next version. Sorry for the confusion...

camner 04-02-2004 10:27 PM

Thanks for all of your help. Please don't take any of comments as criticism, or at least not of the "you should have..." variety. You have a great product, and my comments are intended in the spirit of helping, not carping.

dnanian 04-02-2004 10:57 PM

Totally understood, and taken that way. I'd hoped I'd gotten it right in the documentation, but the nice thing about software is that there's always another version, and another chance to improve things.

Thanks to your help and that of others, SuperDuper will continue to improve.


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