[TAG] Re: Backing up with tar article
kingneutron at yahoo.com
Sat Feb 21 07:47:12 MSK 2004
--Thanks, but you miss the point. Basically what I'd like to have is a
tar-gz.rar. As in:
tar -> gzip -9 -> rar == volume1.rar (100MB), volume2.rar (100MB) ...
--The reason for this is because rar's built-in compression is too slow for
me, but I still want the resulting gzip-compressed backup split into volumes
**on the fly.**
--As of now the only way I can see doing this, is to make a tar.gz and -then-
run rar on it to split it up and add recovery metadata, which requires DOUBLE
the backup storage space. I experimented with the flag that says "process
stdin instead of filenames" but for some reason it can't be used with -v
(volume splitter) -- which kind of defeats the purpose of using rar in the 1st
place; might as well use "split" on the tar.gz at that point. The only thing
you lose there is the recovery metadata.
--Joerg's "star" does what I want, but not with compression in-situ (at least,
not the last time I checked.) That's why I had to make the separate chgvol
script, to compress the resulting 700MB volumes individually. Again, this
requires more temporary backup space while gzip is doing its work. What would
be better is to have star compress on the fly, with a resulting 700MB
--Partimage actually does compressed backups OTF, but is useless for
file-by-file recovery - and doesn't deal with smaller destination partitions
when restoring. For example:
o 4GB partition (hda1) with 2300MB of data
o Partimage -> compressed volumes (basically a DD-alike of the partition)
o Resize partition to 3GB (or try restoring to another HD where hda1 is
o Partimage restore chokes.
--Now here's my complaint: Partimage *claims* that it only backs up the "used"
portions of the disk; why it chokes on restores like that - where the data
should technically fit, if it's only restoring the "used" parts - I have no
idea. Original hda1 was FAT32 and completely defragged, as well. Attempted
restore destination disk was 3GB laptop HD; so when partimage choked, I ended
up using tar over netcat.
--Permission is hereby granted to you to publish this email, blah blah...
Refer to my permission statement in the orig email for specifics. ;-)
--- Thomas Adam <thomas_adam16 at yahoo.com> wrote:
> --- Dave Bechtel <kingneutron at yahoo.com> wrote: >
> > --Note, rar falls under "non-free" in Debian.
> Yes, it does.
> > --I'm not *exactly* sure how to do:
> > ' tar cvf - . |gzip -9 |bkp2rar ' (using ' -m0 ' in the script, which
> > means no
> > rar-compression)
> You can do something like this:
> find . -maxdepth 1 | xargs tar cz myfile.tgz
> No need for your script. That, and:
> might be of interest.
> > ...and have it split into volumes On-The-Fly. Tried some experiments
> > with
> > named pipes (mkfifo) but didn't get anywhere. Any advice on this is
> > welcome.
> That's really overcomplicating things. In either case, use find(1), or use
> the implicit file list to tar (tar -T).
> -- Thomas Adam
> "The Linux Weekend Mechanic" -- http://linuxgazette.net
> "TAG Editor" -- http://linuxgazette.net
> "<shrug> We'll just save up your sins, Thomas, and punish
> you for all of them at once when you get better. The
> experience will probably kill you. :)"
> -- Benjamin A. Okopnik (Linux Gazette Technical Editor)
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