Backup Software - Partial file backup

Author

Partial file backup

bodmzydd@trashmail.net

2006-07-17, 7:13 am

Hi

As well as performing a tape backup of our network, we also run a copy
backup job which synchronises changed files across a point to point
connection to another site.

Is there backup software that will enable you to backup only parts of
files which have changed.

For example, if someone has a large mailbox, a new email would mean
this file has changed. We would not want to backup the entire
mailbox, as this would use a lot of bandwidth, however we would just
like to backup the part of the file that has changed.

Is this possible, and is there any software available which will
enable us to do this?

Thanks

Martin

babi

2006-07-18, 7:14 am

Hi,
What does mean incremental back up ??
Its only take care of this hopefully.
Regds,
babi

bodmzydd@trashmail.net wrote:
> Hi
>
> As well as performing a tape backup of our network, we also run a copy
> backup job which synchronises changed files across a point to point
> connection to another site.
>
> Is there backup software that will enable you to backup only parts of
> files which have changed.
>
> For example, if someone has a large mailbox, a new email would mean
> this file has changed. We would not want to backup the entire
> mailbox, as this would use a lot of bandwidth, however we would just
> like to backup the part of the file that has changed.
>
> Is this possible, and is there any software available which will
> enable us to do this?
>
> Thanks
>
> Martin

bodmzydd@trashmail.net

2006-07-18, 1:16 pm

On 17 Jul 2006 23:40:09 -0700, "babi" <tmohanta@gmail.com> wrote:

>Hi,
> What does mean incremental back up ??
>Its only take care of this hopefully.
>Regds,
>babi
AFAIK an incremental backup would copy the whole of a file if even a
small portion of it has changed. I only want to copy the part of the
file that has changed.

Eg If I have a 2Gb file and a few bytes are changed in the file, I
dont want to copy the entire 2Gb file again.

Howard Kaikow

2006-07-18, 7:13 pm

No general purpose backup program will do that.

--
http://www.standards.com/; See Howard Kaikow's web site.
<bodmzydd@trashmail.net> wrote in message
news:k51qb2tmjjn6e0bhlc8tveul8638mhp6i5@
4ax.com...
> On 17 Jul 2006 23:40:09 -0700, "babi" <tmohanta@gmail.com> wrote:
>
> AFAIK an incremental backup would copy the whole of a file if even a
> small portion of it has changed. I only want to copy the part of the
> file that has changed.
>
> Eg If I have a 2Gb file and a few bytes are changed in the file, I
> dont want to copy the entire 2Gb file again.
>
>
>

J. Yazel

2006-07-19, 1:22 pm

On 17 Jul 2006 23:40:09 -0700, "babi" <tmohanta@gmail.com> wrote:

>Hi,
> What does mean incremental back up ??
>Its only take care of this hopefully.
>Regds,
>babi
> ==================

An incremental backup only backs up files that have changed
since the last backup. The files that are picked for backup are
copied completely.

For instance, if you have 5,000 files in your backup list and only
one file has changed since the last run of that backup list, then
only that file will be becked up this time.

An incremental backup run requires a complete backup the first
time.

Jack

--

Harald

2006-07-25, 1:13 pm

Hi Martin

I am looking for the same solution. If you find a soluion, please let me
know.

<bodmzydd@trashmail.net> wrote in message
news:rermb21f0dc0ofj1r4km0sgansd06rak13@
4ax.com...
>
> Hi
>
> As well as performing a tape backup of our network, we also run a copy
> backup job which synchronises changed files across a point to point
> connection to another site.
>
> Is there backup software that will enable you to backup only parts of
> files which have changed.
>
> For example, if someone has a large mailbox, a new email would mean
> this file has changed. We would not want to backup the entire
> mailbox, as this would use a lot of bandwidth, however we would just
> like to backup the part of the file that has changed.
>
> Is this possible, and is there any software available which will
> enable us to do this?
>
> Thanks
>
> Martin

Howard Kaikow

2006-07-25, 7:13 pm

"Harald" <not@available.com> wrote in message
news:44c65577$1@news.wineasy.se...
> Hi Martin
>
> I am looking for the same solution. If you find a soluion, please let me

NO general purpose program will achieve the goal stated by the OP.

Such a program would have to tried to each app.

A file is just a stream of bytes, no general app can have any idea of how
the bytes are added to/deleted/removed/moved between runs.

Harald

2006-07-26, 7:13 pm

Hi

Yes I understand that no single program can do that, but I thought it should
be possible to make a system running on server A and server B and then the
program (or service) running on server A communicate with a program (or
service) running on server B.
If there is a file that has been updated, I thought the system could use
checksum and find out which part of the file that needs to be updated and
only that part have to be sent over the small bandwith line between the two
servers.

Maybe I am wrong, but I am still dreaming .....

Harald

"Howard Kaikow" <kaikow@standards.com> wrote in message
news:ea63ml$be7$1@pyrite.mv.net...
> "Harald" <not@available.com> wrote in message
> news:44c65577$1@news.wineasy.se...
>
> NO general purpose program will achieve the goal stated by the OP.
>
> Such a program would have to tried to each app.
>
> A file is just a stream of bytes, no general app can have any idea of how
> the bytes are added to/deleted/removed/moved between runs.
>
>

Howard Kaikow

2006-07-27, 1:13 am

The changes WITHIN a file are app specific.

For example:

1. A f[ile contains a list of something..
2. You backup the entire file.
3. You then add, say, 3 items to the end of the list.
4. The partial backup thinks that all it needs to do is backup the added
items.
And at this point, that's OK. But, there's my big butt again!

5. I suddenly realize that I forgot to sort the list, so I sort the list.
6. Now the partial backup program, unless it is somehow linked to the
sorting app, has no choice, it
has to backup the entire file again.

Mark F

2006-08-01, 7:15 pm

I replied to this thread before, but I had some further ideas
about the subject
> Regarding "Partial file backup",
> on Tue, 18 Jul 2006 16:30:17 -0400, in alt.backup-software you wrote:
>
> Filemover:
> http://www.laplink.com/products/filemover/overview.asp
> and
> Laplink (various versions)
> might do what the original poster wants to some extent.
>
> The complete file has to be read on both sides, but with fairly
> high probability only the changed blocks get moved between systems.
>
> However, if the files are "compacted" (meaning that the data in
> the files can move within a file, then "compacting" a file means that
> the entire file has to be moved.
>
> If the files are not compacted then perhaps putting the files on
> a fileserver like from Network Applicances (www.netapp.com) is
> the way to go.
I have realized that as file storage devices become larger with
respect to their speeds, eventually the only way to provide a backup
is to apply the incremental changes to a copy. To improve performance
it is possible to structure things so that only the net incremental
changes are copy to the backup, rather than all of the multiple
changes to the same block.

However, due to the way that things are scaling it eventually will
become impossible to take your state-of-the-art size data storage
and do a complete copy in a reasonable time. (One might say: oh,
I'll use faster interfaces or many "disks" or many "servers", but
in fact the capacity of the "disks" is growing faster than the
speed of the interface on a single disk. Therefore, eventually
you can't make a complete copy every day, week, month, whatever, so
you have to trust to incremental backups.

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