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Old 02-01-2012, 01:18 PM
Alan McKay
 
Default gtar compression achieved

Hey folks,

I looked at the man page and don't see any way to do this - maybe it is a
function of the compression program used I dunno.

Is there any way to get gtar to report on the compression it achieved?

I can't just check file sizes because I'm writing data to tape.

The basic problem is that I know how much data is there to begin with but I
don't know how much room it took up on the tape so I have no idea how much
room is left on the tape.

thanks,
-Alan

--
“Don't eat anything you've ever seen advertised on TV”
- Michael Pollan, author of "In Defense of Food"
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Old 02-01-2012, 02:47 PM
Les Mikesell
 
Default gtar compression achieved

On Wed, Feb 1, 2012 at 8:18 AM, Alan McKay <alan.mckay@gmail.com> wrote:
> Hey folks,
>
> I looked at the man page and don't see any way to do this - maybe it is a
> function of the compression program used I dunno.
>
> Is there any way to get gtar to report on the compression it achieved?
>
> I can't just check file sizes because I'm writing data to tape.
>
> The basic problem is that I know how much data is there to begin with but I
> don't know how much room it took up on the tape so I have no idea how much
> room is left on the tape.

There is a --totals option, but that is before compression. I don't
think there is a way to do it. You can use -f /dev/null and --totals
to get a quick estimate of the uncompressed size of what matches the
tar arguments (for full/incremental). Gnu tar 'special cases' output
to /dev/null and doesn't bother actually reading the data but it adds
up the sizes from the directory. That was added so amanda can do
estimates that let it decide how to mix the fulls and incrementals
each day to fill a tape.

--
Les Mikesell
lesmikesell@gmail.com
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Old 02-01-2012, 02:59 PM
Alan McKay
 
Default gtar compression achieved

>
> There is a --totals option, but that is before compression. I don't
> think there is a way to do it.
>

Dang. THere is a "tell" command on "mt" which tells you what block number
you are on, but according to the man page only exists for some types of
drive. And evidently not mine :-(

That would have worked with some simple math.



--
“Don't eat anything you've ever seen advertised on TV”
- Michael Pollan, author of "In Defense of Food"
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Old 02-01-2012, 03:03 PM
Les Mikesell
 
Default gtar compression achieved

On Wed, Feb 1, 2012 at 9:59 AM, Alan McKay <alan.mckay@gmail.com> wrote:
>>
>> There is a --totals option, but that is before compression. *I don't
>> think there is a way to do it.
>>
>
> Dang. *THere is a "tell" command on "mt" which tells you what block number
> you are on, but according to the man page only exists for some types of
> drive. *And evidently not mine :-(
>
> That would have worked with some simple math.

Is there some reason you aren't using amanda? Give it some holding
disk space and it will run multiple backups at once, buffering on
disk, and figure out how they should go on the tape for you.

--
Les Mikesell
lesmikesell@gmail.com
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Old 02-01-2012, 03:10 PM
Alan McKay
 
Default gtar compression achieved

>
> Is there some reason you aren't using amanda? Give it some holding
> disk space and it will run multiple backups at once, buffering on
> disk, and figure out how they should go on the tape for you.
>


I'm archiving, not backing up.

I looked at Amanda for a few days and it would be really clunky to do what
I want.

Anyway I found this :

[root@solexa-db tmp]# export GZIP=-v
[root@solexa-db tmp]# tar czf files.tar.gz file{1,2,3,4,5}
98.4%

So I'm golden :-)


--
“Don't eat anything you've ever seen advertised on TV”
- Michael Pollan, author of "In Defense of Food"
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Old 02-01-2012, 03:18 PM
Les Mikesell
 
Default gtar compression achieved

On Wed, Feb 1, 2012 at 10:10 AM, Alan McKay <alan.mckay@gmail.com> wrote:
>>
>> Is there some reason you aren't using amanda? *Give it some holding
>> disk space and it will run multiple backups at once, buffering on
>> disk, and figure out how they should go on the tape for you.
>>
>
>
> I'm archiving, not backing up.

Is there some limit to the number of tapes it will track or the length
of a cycle?


> I looked at Amanda for a few days and it would be really clunky to do what
> I want.

I haven't used it for a while, but I thought it had an indexing
mechanism that would let you tell it what you want and it would tell
you the tapes you need and the order to restore them (for full +
incremental cases). And it could re-index the tapes if you lost the
disk copy. Maybe that doesn't fit your use, but it seemed handy.

--
Les Mikesell
lesmikesell@gmail.com
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Old 02-01-2012, 03:22 PM
Alan McKay
 
Default gtar compression achieved

>
> I haven't used it for a while, but I thought it had an indexing
> mechanism that would let you tell it what you want and it would tell
> you the tapes you need and the order to restore them (for full +
> incremental cases). And it could re-index the tapes if you lost the
> disk copy. Maybe that doesn't fit your use, but it seemed handy.
>

In general it is massive overkill for what I"m doing. Even if I wanted to
switch backup solutions and move my backups to Amanda it would not be
worthwhile to get this as an add-on because of the nature of the data I am
dealing with.

Case in point I have about 300G of data that one of the scientists copied
over to my server from a piece of scientific equipment. That 300G was
never in my backups and I never want it to be. But he needs it archived.

Amanda is just way, way too too big for this.

In 2 weeks I've got a program written that is tailored exactly to our
needs. THat's probably less time than it would have taken me to deploy
Amanda. And it would not have been tailored precisely to our needs.

--
“Don't eat anything you've ever seen advertised on TV”
- Michael Pollan, author of "In Defense of Food"
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Old 02-01-2012, 03:32 PM
Les Mikesell
 
Default gtar compression achieved

On Wed, Feb 1, 2012 at 10:22 AM, Alan McKay <alan.mckay@gmail.com> wrote:
>>
>> I haven't used it for a while, but I thought it had an indexing
>> mechanism that would let you tell it what you want and it would tell
>> you the tapes you need and the order to restore them (for full +
>> incremental cases). *And it could re-index the tapes if you lost the
>> disk copy. * Maybe that doesn't fit your use, but it seemed handy.
>>
>
> In general it is massive overkill for what I"m doing. *Even if I wanted to
> switch backup solutions and move my backups to Amanda it would not be
> worthwhile to get this as an add-on because of the nature of the data I am
> dealing with.
>
> Case in point I have about 300G of data that one of the scientists copied
> over to my server from a piece of scientific equipment. * That 300G was
> never in my backups and I never want it to be. *But he needs it archived.
>
> Amanda is just way, way too too big for this.
>
> In 2 weeks I've got a program written that is tailored exactly to our
> needs. *THat's probably less time than it would have taken me to deploy
> Amanda. * And it would not have been tailored precisely to our needs.

'Deploying' amanda is a matter of installing the rpm and editing a
couple of config files about the tape drive, tapes, targets, and
holding space. And maybe some firewall tweaking - but nothing really
complicated. You get a lot of coverage of 'real-world' problems
already built in that will be hard to match in a new program, but you
do have to think the way it does...

--
Les Mikesell
lesmikesell@gmail.com
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Old 02-01-2012, 03:47 PM
John Doe
 
Default gtar compression achieved

From: Les Mikesell <lesmikesell@gmail.com>

> 'Deploying' amanda is a matter of installing the rpm and editing a
> couple of config files about the tape drive, tapes, targets, and
> holding space.* And maybe some firewall tweaking - but nothing really
> complicated.* You get a lot of coverage of 'real-world' problems
> already built in that will be hard to match in a new program, but you
> do have to think the way it does...

An issue with tar is that if you have an error somewhere in
the tar... it is bad news...
afio compress files individually and has other nice things...
Maybe star does it too.

JD
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Old 02-01-2012, 03:50 PM
Les Mikesell
 
Default gtar compression achieved

On Wed, Feb 1, 2012 at 10:47 AM, John Doe <jdmls@yahoo.com> wrote:
>
>> 'Deploying' amanda is a matter of installing the rpm and editing a
>> couple of config files about the tape drive, tapes, targets, and
>> holding space.* And maybe some firewall tweaking - but nothing really
>> complicated.* *You get a lot of coverage of 'real-world' problems
>> already built in that will be hard to match in a new program, but you
>> do have to think the way it does...
>
> An issue with tar is that if you have an error somewhere in
> the tar... it is bad news...
> afio compress files individually and has other nice things...
> Maybe star does it too.

In a practical sense, I don't know if that even matters. I've never
seen a tape drive that could recover and read past an error in the
input anyway. Maybe back in floppy disk days...

--
Les Mikesell
lesmikesell@gmail.com
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