Need copy tool for heavily hardlinked disk
rightsock at gmail.com
Mon Aug 9 18:51:12 UTC 2004
cpio handles hard links, but imho rsync is still probably your best
bet, since it's designed to run incrementally.
Otherwise, it's time to write your own tool. For reference, how many
inodes? (df -i) You may be running out of memory.
On Mon, 9 Aug 2004 11:47:02 -0700, Keith Lofstrom <keithl at kl-ic.com> wrote:
> I need a fast hard disk copy tool, and am looking for suggestions.
> I have a hard drive partition with 170GB of data in it. I want to copy
> the data into a partition (made with more inodes) on another drive.
> Of course, since I am changing the file system on the target, I
> cannot do a simple dd for an exact copy of the partition.
> A file-by-file copy would still be easy, except(!) that the data
> has an enormous number of hard links in it, 120 to 150 hard links
> per file. This slows down the copy by a corresponding factor with
> the common tools. For example, for a 126MB directory, using the
> usual copy procedures, with 120 hard links, the run times are:
> real system
> cp -a: 17m 22s 25s
> piped tar: 18m 10s 26s
> rsync -a: 37m 30s 2m 40s
> Extrapolating to 170GB, that is 400 hours for the cp -a , or more
> than two weeks (!). I have been running a "cp -a" for 4 days now,
> and am about 40% done, so the estimate is not too far off. As far
> as the standard tools can detect, I am moving more than 20 terabytes,
> so without a smart tool that understands hard links this will take
> a very long time.
> So, does anyone have an exotic disk copy tool that can do this more
> efficiently? I would like to use the target disk soon, before
> september at least!
> Keith Lofstrom keithl at ieee.org Voice (503)-520-1993
> KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
> Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs
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