[Dirvish] Copying dirvish vaults (heavily hard linked)
Shawn (Red Mop)
redmopml at comcast.net
Thu Mar 6 16:33:52 UTC 2008
On Thursday 06 March 2008 09:21:53 am Keith Lofstrom wrote:
> A reminder - using any file-level tool (like rsync or cp or dump or
> tar) to copy a complete Dirvish vault, with tens or hundreds of images
> hard-linked together, may take a very long time. Even though the
> final result (preferably using rsync) will be a similar collection
> of hard-linked files of the same size (with only the date stamps on
> the soft-linked files different), the system at the sending end will
> have to walk through every one of the source images. This can take
> many days or even weeks.
>
> It can be easier to just copy the partition as a binary file, then
> use some tool to resize it at the target end. I am learning about
> lvm and the Redhat tool resize2fs (which I just used to double the
> size of an active partition - scary!), and will try them on a
> dirvish bank soon.
>
> See also the ancient: http://wiki.dirvish.org/index.cgi?CopyingDisks
>
> Keith
Tar is actually very fast. I used it to split a bank about a month ago. It
was a little unnerving, so I ran rsync -aH on top of (after) tar, and rsync
did almost nothing. The du -hcs * in each vault already matched.
LVM + resize2fs is one of my very best friends. I grow and shring partions
all the time. It's a real kick to move a partition from one disk to another
while the partition is in use without rebooting, or even taking the partition
offline.
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