tar System Backup - Linux

This is a discussion on tar System Backup - Linux ; I'm a new user to Linux ... trying to escape the "Evil (MS) Empire". If I tar an entire running system from the root, would I be able to restore from a "bare metal" load in the unlikely event of ...

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Thread: tar System Backup

  1. tar System Backup

    I'm a new user to Linux ... trying to escape the "Evil (MS) Empire".

    If I tar an entire running system from the root, would I be able to restore
    from a "bare metal" load in the unlikely event of a crash? (Linux doesn't
    crash, does it?).

    TIA



  2. Re: tar System Backup

    S. Gione wrote:
    > I'm a new user to Linux ... trying to escape the "Evil (MS) Empire".
    >
    > If I tar an entire running system from the root, would I be able to restore
    > from a "bare metal" load in the unlikely event of a crash? (Linux doesn't
    > crash, does it?).
    >
    > TIA
    >
    >

    you can do that. To restore you can boot of a rescue cd, and then untar
    back onto the hard disk. The tricky part is finding a rescue disk that
    includes drivers for both tour hard disk and controller and for you tape
    drive or whatever you tarred onto.

    I've found the gentoo install cd quite useful for this.

    Also with regards to tar, you should have a look at dump and restore.
    They're much better for this sort of operation. dump actually stores an
    index at the start of the tape, so it you want to restore individual
    files it's much quicker to locate them. Also, have a play with the
    interactive mode of resore......very nice

    Alex


  3. Re: tar System Backup

    Alex;

    Thanks for the response ... I hope you don't mind a follow-up question:

    The system in question is an "appliance" (Sun Rac550) meaning it has no
    diskette or other "luxurious" ameneties such as a keyboard or monitor.
    There is, however, a way that the entire system can be re-loaded across the
    LAN, meaning that the end result will be the complete system, but
    unpopulated by user accounts and, of course, data.

    If I have done a tar of the entire (populated) system, once I get back to
    the "bare bones" recovery, do you suspect that a tar -x (from a disk on
    another server) would result in a successful restoral?

    Again, TIA

    "Alex Tomlins" wrote in message
    news:1059161324.389904@ananke.eclipse.net.uk...
    > S. Gione wrote:
    > > I'm a new user to Linux ... trying to escape the "Evil (MS) Empire".
    > >
    > > If I tar an entire running system from the root, would I be able to

    restore
    > > from a "bare metal" load in the unlikely event of a crash? (Linux

    doesn't
    > > crash, does it?).
    > >
    > > TIA
    > >
    > >

    > you can do that. To restore you can boot of a rescue cd, and then untar
    > back onto the hard disk. The tricky part is finding a rescue disk that
    > includes drivers for both tour hard disk and controller and for you tape
    > drive or whatever you tarred onto.
    >
    > I've found the gentoo install cd quite useful for this.
    >
    > Also with regards to tar, you should have a look at dump and restore.
    > They're much better for this sort of operation. dump actually stores an
    > index at the start of the tape, so it you want to restore individual
    > files it's much quicker to locate them. Also, have a play with the
    > interactive mode of resore......very nice
    >
    > Alex
    >




  4. Re: tar System Backup

    No, you can't use "tar" for this. Tar will not backup ACLs,
    filesystem attributes, sockets, devices, (/proc), named pipes,
    and probably other stuff I've forgotten.

    You need a native "dump" utility that knows all about that stuff.
    ext2 and 2 have "dump" and "restore".

    I seem to remember "star" that uses "pax" file format, to backup
    more stuff than tar does. But if you want a complete restore
    on a new disk after a disk crash, you want dump. Tar is for
    archives, not backups. (There is a subtle difference, I think.)

    Hope this helps!

    -Wayne

    S. Gione wrote:

    > I'm a new user to Linux ... trying to escape the "Evil (MS) Empire".
    >
    > If I tar an entire running system from the root, would I be able to restore
    > from a "bare metal" load in the unlikely event of a crash? (Linux doesn't
    > crash, does it?).
    >
    > TIA
    >
    >



  5. Re: tar System Backup

    Yes, you can backup nicely using tar. However, you really really want
    to review the tar man and other materials you can find around. My
    style is I go into the node I want to tar from and down from, and I
    just say,

    tar cvzf node.tgz *

    and tar recursively saves the whole thing. To retrieve the whole
    thing I make a node label, put my node.tgz file under it, and say,

    tar xvzf node.tgz

    which restores the tree under that nodename. I shouldn't need to say,
    play and practice with this until you are really really sure of it
    before you try anything serious.

    Now for the details. If you tar a whole tree and for whatever reason,
    when you come to extract it, it blows it, then your whole tree is at
    risk. So in addition to saving old tarballs, you can do a little
    strategy.

    Namely, you can have more than one tree off your root or base
    directory. Thus you have a few very large branches rather than one
    single giant one. Further, some of those branches will be more
    valuable than others, and can be backed-up more frequently. My own
    tree is thus separated at its base into 6 or 7 major branches which I
    can tar separately as needed.

    One of these days I'm going to bring in a CDROM burner and save my
    backups onto write-once CDs. And save the old ones for *years*.
    Because, the best computer hardware makes a mistake once in a great
    while; and once the mistake is in there, it will propagate right down
    through time. So if you feel you don't need those old backups, OK,
    just save them anyhow.

    *And Don't* keep them all in a handy box beside your computer! Save
    your best ones off-site somewhere, or even three or four somewheres if
    you are doing something very serious like your PhD research and
    dissertation. And always carry another backup *with you* when you
    travel.

    Cheers -- Martha Adams



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