Resizable Loopback and Rsync Windows - Linux

This is a discussion on Resizable Loopback and Rsync Windows - Linux ; Hi All, I'm wondering if the following is possible. - Having a 'loopback' filesystem that you can grow as you require (and shrink if possible). A bit like tmpfs. I already know you can do the following: - - Take ...

+ Reply to Thread
Results 1 to 3 of 3

Thread: Resizable Loopback and Rsync Windows

  1. Resizable Loopback and Rsync Windows

    Hi All,

    I'm wondering if the following is possible.
    - Having a 'loopback' filesystem that you can grow as you require
    (and shrink if possible). A bit like tmpfs.

    I already know you can do the following: -
    - Take an existing loopback filesystem (say ext2 in a 100Mb file), dd
    on some zeros on the end and use resizefs on the filesystem to grow it.
    - To shrink, use resizefs to shrink it, then dd the whole file to
    another (smaller) file.


    My reason for this is that I use rsync to backup many machines. For
    linux this works very well as I can rsync a whole linux box to another
    linux backup server and know all the permissions, symlinks etc are
    copied across perfectly. Its fast and efficient.

    If the box I'm backing a linux box up to is a windows box, my options
    are more limited. I could just Tar Gzip it to a massive file and upload
    it to a SMB share, but for a 100Gb server this takes a LONG time and
    lots of bandwidth.

    I had a thought the other day that I could just create a massive file on
    the windows share, mount it via SMB as a loopback filesystem and rsync
    to that. It would work and retain all the benefits of rsync. However it
    would be nice if the loopback filesystem worked like tmpfs and grew as
    needed.

    What are your thoughts on implementing this. Currently I'm resigned to
    scripting the 'grow filesystem' method I outlined above and have it
    watchdog the file during backup, growing it on demand, or more likely
    working out how big the backup is and growing the file before the backup.


    Brendan Grieve

  2. Re: Resizable Loopback and Rsync Windows

    On Fri, 01 Jun 2007 09:28:18 +0800, removethis typed this message:

    > Hi All,
    >
    > I'm wondering if the following is possible.
    > - Having a 'loopback' filesystem that you can grow as you require
    > (and shrink if possible). A bit like tmpfs.
    >
    > I already know you can do the following: -
    > - Take an existing loopback filesystem (say ext2 in a 100Mb file), dd
    > on some zeros on the end and use resizefs on the filesystem to grow it.
    > - To shrink, use resizefs to shrink it, then dd the whole file to
    > another (smaller) file.
    >
    >
    > My reason for this is that I use rsync to backup many machines. For
    > linux this works very well as I can rsync a whole linux box to another
    > linux backup server and know all the permissions, symlinks etc are
    > copied across perfectly. Its fast and efficient.
    >
    > If the box I'm backing a linux box up to is a windows box, my options
    > are more limited. I could just Tar Gzip it to a massive file and upload
    > it to a SMB share, but for a 100Gb server this takes a LONG time and
    > lots of bandwidth.
    >
    > I had a thought the other day that I could just create a massive file on
    > the windows share, mount it via SMB as a loopback filesystem and rsync
    > to that. It would work and retain all the benefits of rsync. However it
    > would be nice if the loopback filesystem worked like tmpfs and grew as
    > needed.
    >
    > What are your thoughts on implementing this. Currently I'm resigned to
    > scripting the 'grow filesystem' method I outlined above and have it
    > watchdog the file during backup, growing it on demand, or more likely
    > working out how big the backup is and growing the file before the
    > backup.
    >
    >
    > Brendan Grieve


    Sounds complicated. Why not just install a Rsync for Windows
    application? The you would need the extra risk and cpu load to compress
    a tar.gz file.

    Google "rsync windows"


  3. Re: Resizable Loopback and Rsync Windows



    noi ance wrote:
    > On Fri, 01 Jun 2007 09:28:18 +0800, removethis typed this message:
    >
    >> Hi All,
    >>
    >> I'm wondering if the following is possible.
    >> - Having a 'loopback' filesystem that you can grow as you require
    >> (and shrink if possible). A bit like tmpfs.
    >>
    >> I already know you can do the following: -
    >> - Take an existing loopback filesystem (say ext2 in a 100Mb file), dd
    >> on some zeros on the end and use resizefs on the filesystem to grow it.
    >> - To shrink, use resizefs to shrink it, then dd the whole file to
    >> another (smaller) file.
    >>
    >>
    >> My reason for this is that I use rsync to backup many machines. For
    >> linux this works very well as I can rsync a whole linux box to another
    >> linux backup server and know all the permissions, symlinks etc are
    >> copied across perfectly. Its fast and efficient.
    >>
    >> If the box I'm backing a linux box up to is a windows box, my options
    >> are more limited. I could just Tar Gzip it to a massive file and upload
    >> it to a SMB share, but for a 100Gb server this takes a LONG time and
    >> lots of bandwidth.
    >>
    >> I had a thought the other day that I could just create a massive file on
    >> the windows share, mount it via SMB as a loopback filesystem and rsync
    >> to that. It would work and retain all the benefits of rsync. However it
    >> would be nice if the loopback filesystem worked like tmpfs and grew as
    >> needed.
    >>
    >> What are your thoughts on implementing this. Currently I'm resigned to
    >> scripting the 'grow filesystem' method I outlined above and have it
    >> watchdog the file during backup, growing it on demand, or more likely
    >> working out how big the backup is and growing the file before the
    >> backup.
    >>
    >>
    >> Brendan Grieve

    >
    > Sounds complicated. Why not just install a Rsync for Windows
    > application? The you would need the extra risk and cpu load to compress
    > a tar.gz file.
    >
    > Google "rsync windows"
    >



    For two reasons: -
    a) I don't have any further access to the server apart from as a smb
    share

    b) To rsync to it, you don't technically need an rsync daemon on the
    otherside (although it would speed things up by locally indexing the
    files). However, have you ever tried to rsync an xfs/ext3/ext2
    filesystem (I'm talking about from /) to an NTFS system. Its nasty!

    Also, I'm trying to avoid tar.gz a file for the following reasons: -
    a) It means transferring over EVERYTHING each backup

    b) Higher CPU on compression etc... Not that I'm too worried, this is
    a quad cpu quad core.


    Brendan

+ Reply to Thread