Discussion:
Really Nasty Backup Problem
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Robert Peirce
2017-12-02 14:04:24 UTC
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I have my pictures and music on a HD that I backup to another HD. I
never change or delete, just add.

Yesterday iTunes couldn't find an album. When I went to look for it, it
wasn't there, nor was it on the backup because the backup is a clone of
the source. When the album was deleted from the source it was deleted
from the backup on the next run.

In all my years of paranoid backing up this is the first time this has
happened and I am looking for a solution. As an experiment I ran a diff
on the two iTunes systems and it took 11 hours. That won't work because
the backup usually takes a few minutes.

What I need is a backup program that can be set not to delete a file on
the backup without permission. Does such exist?

It occurs to me that potentially equally a problem is replacing a file
that has changed but that may really be less of a problem.
Nevertheless, asking permission before changing/updating might also be good.
Alrescha
2017-12-02 16:56:37 UTC
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Post by Robert Peirce
What I need is a backup program that can be set not to delete a file on
the backup without permission. Does such exist?
rsync
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A.
Robert Peirce
2017-12-02 17:47:24 UTC
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Post by Robert Peirce
What I need is a backup program that can be set not to delete a file on
the backup without permission. Does such exist?
rsync
I read the man page, which is pretty heavy going. It looks like it will
copy from source to destination, but it isn't clear if it updates or
deletes anything that is different and more important, if it can do that
is there a way to require permission before proceeding?

The -n option does a dry run and shows what is to be done. Depending on
how long that takes it could give me what I need. Then I could make any
corrections before running the usual backup software.

Actually, I'm having a difficult time even figuring out how to structure
a command. I could play with it but can you offer some advice?
nospam
2017-12-02 17:58:43 UTC
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Post by Robert Peirce
Post by Robert Peirce
What I need is a backup program that can be set not to delete a file on
the backup without permission. Does such exist?
rsync
I read the man page, which is pretty heavy going. It looks like it will
copy from source to destination, but it isn't clear if it updates or
deletes anything that is different and more important, if it can do that
is there a way to require permission before proceeding?
The -n option does a dry run and shows what is to be done. Depending on
how long that takes it could give me what I need. Then I could make any
corrections before running the usual backup software.
Actually, I'm having a difficult time even figuring out how to structure
a command. I could play with it but can you offer some advice?
don't waste your time.

get an actual backup program, such as carbon copy cloner.
Alrescha
2017-12-03 00:29:20 UTC
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Post by Robert Peirce
Actually, I'm having a difficult time even figuring out how to structure
a command. I could play with it but can you offer some advice?
rsync, by default, adds to your backup. It does not delete. The
cognoscenti here will tell you to use CCC, without mentioning that it is
primarily a GUI for rsync.

‘rsync -av /Volumes/source /Volumes/dest’ will create a copy of source on
dest in a folder called ‘source’.

Two caveats, the first being that the version of rsync that comes with
macOS is old, you might want Macports or homebrew. Second, rsync is slow -
it’s much faster if you make your initial copy with cp, but of course
that’s another command to figure out.

For what it’s worth, I back up 20 TB of data each month with ‘rsync -ahvPX
/Volumes/source/ /Volumes/dest’ (that command does not create a folder). I
use nothing else.
--
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Chris Ridd
2017-12-02 17:27:40 UTC
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I have my pictures and music on a HD that I backup to another HD.  I
never change or delete, just add.
Yesterday iTunes couldn't find an album.  When I went to look for it, it
wasn't there, nor was it on the backup because the backup is a clone of
the source.  When the album was deleted from the source it was deleted
from the backup on the next run.
Post by Robert Peirce
In all my years of paranoid backing up this is the first time this has
happened and I am looking for a solution.  As an experiment I ran a diff
on the two iTunes systems and it took 11 hours.  That won't work because
the backup usually takes a few minutes.
What I need is a backup program that can be set not to delete a file on
the backup without permission.  Does such exist?
That would be incredibly inconvenient. I think what you want is
something that does incremental backups, but which leaves the
intermediate historical states on your backup disk. A bit like Time Machine.

Why don't you just use Time Machine?
--
Chris
Jolly Roger
2017-12-02 18:31:43 UTC
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Post by Robert Peirce
I have my pictures and music on a HD that I backup to another HD. I
never change or delete, just add.
Yesterday iTunes couldn't find an album. When I went to look for it, it
wasn't there, nor was it on the backup because the backup is a clone of
the source. When the album was deleted from the source it was deleted
from the backup on the next run.
That means you are using a really shitty "backup" solution. How are you
backing up?
Post by Robert Peirce
In all my years of paranoid backing up this is the first time this has
happened and I am looking for a solution.
Time Machine.
--
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
Robert Peirce
2017-12-02 19:00:15 UTC
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Post by Jolly Roger
That means you are using a really shitty "backup" solution. How are you
backing up?
I'm using SD! but I'm told CCC is the same. Both produce a clone by
adding, updating and deleting to make the destination look like the
source. That's fine 99% of the time but not if you inadvertently delete
something on the source and then do a backup.

Although I have CCC, I use SD! because I've used it for years and
haven't wanted to make the switch. However, I asked Shirt Pocket if
there was a way to issue a warning and prevent the deletion phase of the
backup. There isn't. I'm trying to find a backup solution that can do
that.
Post by Jolly Roger
Post by Robert Peirce
In all my years of paranoid backing up this is the first time this has
happened and I am looking for a solution.
Time Machine.
That is a solution I use on my MBP, but this is an add-on HD that I also
connect to other computers that can deal with iTunes. Can Time Machine
even work with this?

When I open Time Machine preferences it allows me to select the
destination drive but not the source. The add-on drives are in the
exclude list and I guess I could include them but how do I restrict
backups to ONLY use the external HD as a source? Please let me know how
because it definitely would solve my problem.
nospam
2017-12-02 19:07:11 UTC
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Post by Robert Peirce
Post by Jolly Roger
That means you are using a really shitty "backup" solution. How are you
backing up?
I'm using SD! but I'm told CCC is the same.
they're similar, but not the same. ccc does *much* more than sd.
Post by Robert Peirce
Both produce a clone by
adding, updating and deleting to make the destination look like the
source. That's fine 99% of the time but not if you inadvertently delete
something on the source and then do a backup.
in addition to straight clones, ccc can archive previous versions, what
they call a safety net.
Post by Robert Peirce
Although I have CCC, I use SD! because I've used it for years and
haven't wanted to make the switch. However, I asked Shirt Pocket if
there was a way to issue a warning and prevent the deletion phase of the
backup. There isn't. I'm trying to find a backup solution that can do
that.
clones have to delete for it to be a clone.

ccc can archive older versions.
Post by Robert Peirce
Post by Jolly Roger
Post by Robert Peirce
In all my years of paranoid backing up this is the first time this has
happened and I am looking for a solution.
Time Machine.
That is a solution I use on my MBP, but this is an add-on HD that I also
connect to other computers that can deal with iTunes. Can Time Machine
even work with this?
yes.
Post by Robert Peirce
When I open Time Machine preferences it allows me to select the
destination drive but not the source. The add-on drives are in the
exclude list and I guess I could include them but how do I restrict
backups to ONLY use the external HD as a source? Please let me know how
because it definitely would solve my problem.
select it and then delete it from the exclude list.
Robert Peirce
2017-12-02 19:37:37 UTC
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Post by nospam
Post by Robert Peirce
When I open Time Machine preferences it allows me to select the
destination drive but not the source. The add-on drives are in the
exclude list and I guess I could include them but how do I restrict
backups to ONLY use the external HD as a source? Please let me know how
because it definitely would solve my problem.
select it and then delete it from the exclude list.
This seems to work. Tell me if I am wrong. I removed Pictures from the
exclude list and added Macintosh HD. Pictures is the name of the add-on
drive I use for pictures and music. Macinosh HD, of course, is the
computer's internal drive. If this is correct, Pictures will backup to
Time Machine but Macintosh HD will not.
Jolly Roger
2017-12-02 21:08:19 UTC
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Post by Robert Peirce
Post by Jolly Roger
That means you are using a really shitty "backup" solution. How are
you backing up?
I'm using SD! but I'm told CCC is the same. Both produce a clone by
adding, updating and deleting to make the destination look like the
source. That's fine 99% of the time but not if you inadvertently
delete something on the source and then do a backup.
Although I have CCC, I use SD! because I've used it for years and
haven't wanted to make the switch. However, I asked Shirt Pocket if
there was a way to issue a warning and prevent the deletion phase of
the backup. There isn't. I'm trying to find a backup solution that
can do that.
No, what you want is an incremental backup solution like Time Machine,
where you can restore files from the backup that have long been deleted
on the computer just by rolling back to the appropriate snapshot and
restoring that file from it. And as a bonus, Time Machine does indeed
issue a warning whenever it runs so low on space on the storage volume
that it needs to delete a previous snapshot.
Post by Robert Peirce
That is a solution I use on my MBP, but this is an add-on HD that I
also connect to other computers that can deal with iTunes. Can Time
Machine even work with this?
Don't do that. As a best practice you should never use a backup medium
for anything other than backups. Otherwise you put your backup data at
risk. Time Machine is designed to consume as much space on the backup
drive as needed for backups, which means it will eventually fill up,
especially if you continue to add extraneous non-backup files to it.
You should always use a dedicated drive for backups.
Post by Robert Peirce
When I open Time Machine preferences it allows me to select the
destination drive but not the source. The add-on drives are in the
exclude list and I guess I could include them but how do I restrict
backups to ONLY use the external HD as a source? Please let me know
how because it definitely would solve my problem.
Use Time Machine to backup your entire system including this external
drive to a dedicated backup drive. Problem solved.
--
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
Robert Peirce
2017-12-02 22:45:24 UTC
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Post by Jolly Roger
Post by Robert Peirce
That is a solution I use on my MBP, but this is an add-on HD that I
also connect to other computers that can deal with iTunes. Can Time
Machine even work with this?
Don't do that. As a best practice you should never use a backup medium
for anything other than backups. Otherwise you put your backup data at
risk. Time Machine is designed to consume as much space on the backup
drive as needed for backups, which means it will eventually fill up,
especially if you continue to add extraneous non-backup files to it.
You should always use a dedicated drive for backups.
I'm sorry. I wasn't clear. I move my pictures/music HD to different
machines, not the backups! They only backup an individual machine.

As mentioned in a previous post I think I have a Time Machine backup set
up correctly to backup my pictures/music add-on HD but not the built-in
HD in the computer. This is running now but it will be several more
hours before the initial write completes and I can be positive it is
really doing what I want. However, I'm pretty sure it is.
Neill Massello
2017-12-02 23:03:48 UTC
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Post by Robert Peirce
I'm sorry. I wasn't clear. I move my pictures/music HD to different
machines, not the backups! They only backup an individual machine.
It sounds like what you want is not a backup or a clone but an archive:
a disk to which new items are added automatically but from which old
items (no longer present on the source volume) are only deleted
manually. You want a utility that does one-way synchronization. I
mentioned two in my other post in this thread.
Bernd Fröhlich
2017-12-05 10:47:26 UTC
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Post by Robert Peirce
I'm using SD! but I'm told CCC is the same. Both produce a clone by
adding, updating and deleting to make the destination look like the
source. That's fine 99% of the time but not if you inadvertently delete
something on the source and then do a backup.
Although I have CCC, I use SD! because I've used it for years and
haven't wanted to make the switch. However, I asked Shirt Pocket if
there was a way to issue a warning and prevent the deletion phase of the
backup. There isn't. I'm trying to find a backup solution that can do
that.
Maybe there isn´t a way to issue a warning, but SuperDuper can still do
what you want (without the warning).

Just click on "Options.." and then chose "Copy newer files" or "Copy
different files" instead of "Smart Update".
Robert Peirce
2017-12-09 15:39:22 UTC
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Post by Bernd Fröhlich
Post by Robert Peirce
I'm using SD! but I'm told CCC is the same. Both produce a clone by
adding, updating and deleting to make the destination look like the
source. That's fine 99% of the time but not if you inadvertently delete
something on the source and then do a backup.
Although I have CCC, I use SD! because I've used it for years and
haven't wanted to make the switch. However, I asked Shirt Pocket if
there was a way to issue a warning and prevent the deletion phase of the
backup. There isn't. I'm trying to find a backup solution that can do
that.
Maybe there isn´t a way to issue a warning, but SuperDuper can still do
what you want (without the warning).
Just click on "Options.." and then chose "Copy newer files" or "Copy
different files" instead of "Smart Update".
Thanks. That's almost the ticket except I want to copy new AND
different, which isn't an option. However, I think I will contact Shirt
Pocket about it. It shouldn't be that difficult
Robert Peirce
2017-12-09 16:00:28 UTC
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Thanks.  That's almost the ticket except I want to copy new AND
different, which isn't an option.  However, I think I will contact Shirt
Pocket about it.  It shouldn't be that difficult
It turns out copy new includes different. Sort of obvious when I think
about it.
Robert Peirce
2017-12-09 16:08:57 UTC
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It turns out copy new includes different.  Sort of obvious when I think
about it.
It also turns out SD! remembers what you selected and tries to apply it
to a backup that you do want to run smart. Too bad the mode can't be
tied to the source. Inadvertently forgetting to make the right
selection could wipe out everything you've done to that point. I guess
I need to keep Time Machine running just in case.

Neill Massello
2017-12-02 21:46:06 UTC
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Post by Robert Peirce
What I need is a backup program that can be set not to delete a file on
the backup without permission. Does such exist?
In spades. Most backup and synchronization apps can be set not to delete
an item in the destination that is no longer present in the source. What
software were you using?
Post by Robert Peirce
It occurs to me that potentially equally a problem is replacing a file
that has changed but that may really be less of a problem.
Nevertheless, asking permission before changing/updating might also be good.
The better synchronization apps will allow for a "trial sync" or preview
that will list the changes that will be made when the sync is actually
run.

If you want simple (and inexpensive), try File Synchronization.

<http://www.nemesys-soft.com/MacOS/FileSynchronization/FileSynchronization_EN.html>

If you want fancy, the overwhelming favorite is ChronoSync.

<https://www.econtechnologies.com/chronosync/overview.html>
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