Copying backup files

[Gene E. Bloch]

Thanks for this - it does seem to confirm my presumption, although I
note that you haven't experienced large incrementals as a result. I
still think it's a messy way to do file backups, though - although I
certainly recognise the value of a system image.

I have mixed feelings about it. It's a bit counter-intuitive, but at the
same time, it makes some sense. If properly done you certainly should
end up with an image that reflects accurately the state of the partition
at the time of backup (granted that Shadowing is black magic, in terms
of my understanding), and it ought to be more efficient that rewriting
entire files when only one cluster has changed.

I'm not sure why Macrium doesn't seem to do the same analysis before a
clone. Maybe they do, and I just don't realize it.

 

[Philip Herlihy]

.

I have mixed feelings about it. It's a bit counter-intuitive, but at the
same time, it makes some sense. If properly done you certainly should
end up with an image that reflects accurately the state of the partition
at the time of backup (granted that Shadowing is black magic, in terms
of my understanding), and it ought to be more efficient that rewriting
entire files when only one cluster has changed.

I'm not sure why Macrium doesn't seem to do the same analysis before a
clone. Maybe they do, and I just don't realize it.

I haven't used Macrium, but I have used Acronis True Image, and that has
a facility to do what they call a 'Differential' backup. But it works
at the Sector level, not the file level. I was interested in your
report that defragging a disk doesn't seem to generate spurious
differential backups - perhaps defragging also works at the Sector level
- below my radar, I'm afraid. Surely it can't be as space-efficient,
though. If you change one tiny text file, you have to back up the
entire sector, typically 4K. I guess it's conceivable that such
products might be able to back up only part of a file, perhaps, which
could make them more space-efficient. Ah - just found this in the
Acronis True Image Home 2012 Help:

"An incremental or differential backup created after a disk is
defragmented might be considerably larger than usual. This is because
the defragmentation program changes file locations on the disk and the
backups reflect these changes. Therefore, it is recommended that you re-
create a full backup after disk defragmentation."

 

[Gene E. Bloch]

I haven't used Macrium, but I have used Acronis True Image, and that has
a facility to do what they call a 'Differential' backup. But it works
at the Sector level, not the file level. I was interested in your
report that defragging a disk doesn't seem to generate spurious
differential backups - perhaps defragging also works at the Sector level
- below my radar, I'm afraid. Surely it can't be as space-efficient,
though. If you change one tiny text file, you have to back up the
entire sector, typically 4K. I guess it's conceivable that such
products might be able to back up only part of a file, perhaps, which
could make them more space-efficient. Ah - just found this in the
Acronis True Image Home 2012 Help:

"An incremental or differential backup created after a disk is
defragmented might be considerably larger than usual. This is because
the defragmentation program changes file locations on the disk and the
backups reflect these changes. Therefore, it is recommended that you re-
create a full backup after disk defragmentation."

Odds are that the same would be true of Macrium, then, since they use
the same approach.

Surely the people at Acronis, at least, are more knowledgeable than I
am, wouldn't you think? So you might have just forced me to abandon a
prejudice or two

 

[Philip Herlihy]

....

I backup to external HDDs that are plugged into USB, and I use a
manually-initiated automatic backup program (MS Sync Toy) to compare PC
against backup drive and copy just the new/changed files. I definitely want
a backup which makes an exact copy of each file, rather than something that
merges the whole backup into one big proprietary file because it's a pain
searching through that if you want to restore a file, and if the file gets
corrupted you've lost everything.

....

Backups were originally usually sent to tape - hence the large
'archive' file format. I've seen no appreciable problems due to this
(including PST files, etc).

Your scheme doesn't scale to a situation where you have a dozen users
changing files daily, and you find you need to go back a couple of
months of daily backups to get an undamaged file. I persuaded one
customer of this a couple of months ago, and a couple of weeks later she
realised she'd accidentally deleted large parts of a vital spreadsheet
before saving it. (Easy to do with many types of file if you select
more than you intended to, and the overtype it.) We found an intact
original from a point just after I'd sorted out a 'proper' backup regime
for her. All the subsequent versions were exact copies of the damaged
file.

For me, a utility only deserves the name 'Backup' if it captures a
sequence of all versions of a file, and is aware of the Archive
attribute. Anything else is just a copy, and rubbish copied is still
rubbish.

It's worth noting that DropBox, Google Docs and Skydrive maintain
versions of files (for Skydrive, only Office files) if you edit the
files through those sites.

 

[Philip Herlihy]

Odds are that the same would be true of Macrium, then, since they use
the same approach.

Surely the people at Acronis, at least, are more knowledgeable than I
am, wouldn't you think? So you might have just forced me to abandon a
prejudice or two

The older you get, the more you know. And the less you're certain of
any of it...

 

[Robin Bignall]

The older you get, the more you know. And the less you're certain of
any of it...

True. I know less than anyone about how disks operate in detail, but I
suppose common sense will tell us that there must be trade-offs. For
example, if you have a system that examines in some way the sectors to
just backup those that have changed, this operation must take time,
during which many other sectors will change on a very busy disk (or even
SSD). I can't see how, in that case, one can end up with an accurate
image of one instant, even though CPUs are very much faster than I/O
devices. I don't know if Shadow Protect does it at the sector level for
incrementals or differentials, or some unit larger, but their idea is to
capture an image in the shortest possible time, and then write it out to
a disk at leisure, in parallel with other processing. Disk space is
cheap; it doesn't matter how large incrementals are with that approach.

 

[Philip Herlihy]

True. I know less than anyone about how disks operate in detail, but I
suppose common sense will tell us that there must be trade-offs. For
example, if you have a system that examines in some way the sectors to
just backup those that have changed, this operation must take time,
during which many other sectors will change on a very busy disk (or even
SSD). I can't see how, in that case, one can end up with an accurate
image of one instant, even though CPUs are very much faster than I/O
devices. I don't know if Shadow Protect does it at the sector level for
incrementals or differentials, or some unit larger, but their idea is to
capture an image in the shortest possible time, and then write it out to
a disk at leisure, in parallel with other processing. Disk space is
cheap; it doesn't matter how large incrementals are with that approach.

All true (providing you are taking incrementals and not copying
everything every time, and especially not overwriting previous copies).
However, if I want to restore a particular file, the fact that the
backup archive is structured in terms of sectors seems an unecessary
complication. I certainly value disk images, which work via sectors,
but my own feeling is that it's a stretch to use that technology for
simple file backup, which is a mature field of its own.

 

[Robin Bignall]

All true (providing you are taking incrementals and not copying
everything every time, and especially not overwriting previous copies).
However, if I want to restore a particular file, the fact that the
backup archive is structured in terms of sectors seems an unecessary
complication. I certainly value disk images, which work via sectors,
but my own feeling is that it's a stretch to use that technology for
simple file backup, which is a mature field of its own.

ShadowProtect incrementals run every two hours on my machine during the
week. They only copy what's changed, and neither they, nor full backups,
copy free space unless you want them to. The Incs are strung out
separately "below" the full to which they refer; they don't overwrite
the previous Inc.

SP, along with other systems, has a Mount command for any image. It
presents the image's files in a Windows Explorer format and you can copy
any file out of the image. It also has a Write option so that you can
copy any file INTO the image. The image, when demounted, will then
create a slightly expanded Inc that contains the new data. I seldom use
this facility unless, say, I want to shrink an image to, say, restore to
a smaller device.

I agree with you about file backup, and there are systems that are based
on a file, rather than a volume, method. SP, however, has met all of my
needs, so far.

 

[Gene E. Bloch]

All true (providing you are taking incrementals and not copying
everything every time, and especially not overwriting previous copies).
However, if I want to restore a particular file, the fact that the
backup archive is structured in terms of sectors seems an unecessary
complication. I certainly value disk images, which work via sectors,
but my own feeling is that it's a stretch to use that technology for
simple file backup, which is a mature field of its own.

I'm not sure how or why this bothers you. You don't need to (can't, in
fact) deal directly with the way the files are backed up or with the way
the backups are structured. If you need to restore an entire drive, the
program does it for you. If you need to reclaim a file or files, the
program mounts the backup and you see it as a Windows disk drive. You
can just copy files or folders at will, as needed. In both cases you can
choose a backup of a specific date, if there is a series of
incrementals.

There's a twist (in Macrium, at least), in that when you mount an image,
you have to notice & check an obscure checkbox in order to mount it with
full access. Otherwise you get unpleasant surprises when you try to
access things like your Documents

 

[Philip Herlihy]

ShadowProtect incrementals run every two hours on my machine during the
week. They only copy what's changed, and neither they, nor full backups,
copy free space unless you want them to. The Incs are strung out
separately "below" the full to which they refer; they don't overwrite
the previous Inc.

SP, along with other systems, has a Mount command for any image. It
presents the image's files in a Windows Explorer format and you can copy
any file out of the image. It also has a Write option so that you can
copy any file INTO the image. The image, when demounted, will then
create a slightly expanded Inc that contains the new data. I seldom use
this facility unless, say, I want to shrink an image to, say, restore to
a smaller device.

I agree with you about file backup, and there are systems that are based
on a file, rather than a volume, method. SP, however, has met all of my
needs, so far.

Seems you can only buy it 5 licenses at a time ($89).

 

[Philip Herlihy]

I'm not sure how or why this bothers you. You don't need to (can't, in
fact) deal directly with the way the files are backed up or with the way
the backups are structured. If you need to restore an entire drive, the
program does it for you. If you need to reclaim a file or files, the
program mounts the backup and you see it as a Windows disk drive. You
can just copy files or folders at will, as needed. In both cases you can
choose a backup of a specific date, if there is a series of
incrementals.

There's a twist (in Macrium, at least), in that when you mount an image,
you have to notice & check an obscure checkbox in order to mount it with
full access. Otherwise you get unpleasant surprises when you try to
access things like your Documents

Well, when MS designed a backup facility for Windows Vista, they chose
to separate sector-based imaging from file-based backups, and that just
feels right to me.

 

[Robin Bignall]

Seems you can only buy it 5 licenses at a time ($89).

It's certainly not cheap, but I didn't realise my licence covers 5
machines.

 

[Gene E. Bloch]

Well, when MS designed a backup facility for Windows Vista, they chose
to separate sector-based imaging from file-based backups, and that just
feels right to me.

File-based backup, in my experience, means a backup scheme wherein you
save a specific chosen set of files and folders as just saved data with
no other data saved. You can recover only the files you initially chose
to save since they are the only ones that get saved.

Image-based backups, like clones, mean backups where what you save is a
complete version of the partition or drive that is backed up. You can
recover any file, including the entire hard drive boot structure if
needed.

I like images and clones precisely because I don't need to decide today
what I might need in the future, with the potential problem that the one
I need next Thursday will be one of the files I didn't select to back
up.

 

[Gene E. Bloch]

It's certainly not cheap, but I didn't realise my licence covers 5
machines.

If you guys are talking about the ShadowProtect that is found at

http://www.storagecraft.com/

I just looked there. I see a single Desktop Edition license at $89.95
and a three-user license (Desktop Edition - Home User Bundle) at
$209.95.

I'd say fairly expensive.

 

[Rodney Pont]

If you guys are talking about the ShadowProtect that is found at

http://www.storagecraft.com/

I just looked there. I see a single Desktop Edition license at $89.95
and a three-user license (Desktop Edition - Home User Bundle) at
$209.95.

I'd say fairly expensive.

Could the confusion here be that it's ShadowProtect version 5?
(ie ShadowProtect 5 $89.99)

 

[Gene E. Bloch]

Could the confusion here be that it's ShadowProtect version 5?
(ie ShadowProtect 5 $89.99)

Yeah, I can believe that

It is written as 'SHADOWPROTECT 5'. The '5' is very prominent & it isn't
adorned with the word 'version' or any abbreviation of it.

 

[Robin Bignall]

Could the confusion here be that it's ShadowProtect version 5?
(ie ShadowProtect 5 $89.99)

Yes, probably. That's the latest version.

 

[Char Jackson]

I like images and clones precisely because I don't need to decide today
what I might need in the future, with the potential problem that the one
I need next Thursday will be one of the files I didn't select to back
up.

+1

 

[Philip Herlihy]

If you guys are talking about the ShadowProtect that is found at

http://www.storagecraft.com/

I just looked there. I see a single Desktop Edition license at $89.95
and a three-user license (Desktop Edition - Home User Bundle) at
$209.95.

I'd say fairly expensive.

I think I must have mis-read "5 Desktop", which does appear on the
page... (a senior moment).

 

[Gene E. Bloch]

I think I must have mis-read "5 Desktop", which does appear on the
page... (a senior moment).

Senior, but probably not serious

Actually, there was a post above from Rodney Pont, who guessed as much.
Thanks for the proof (we need proof!).