Re: Best way to copy whole content of HD into another

On Wed, 12 Apr 2006 12:40:02 +1000 in <4a37k5Fq5sd7U1@xxxxxxxxxxxxxx> Jean-Yves Avenard <me@xxxxxxxxxxx> wrote:

Okay. I'll be blunt. You lack clue.
Your lack of clue makes me suspect that you'll incur data loss
and corruption no matter what you do.

With that stated, here are scissors to run with.
0) Whatever backup/restore/disaster recovery mechanism you have
in place already
Pro: Should be thoroughly tested already and allow restore of data
to a different machine. Designed to handle large quantities of
data on a regular basis.
Con: You probably don't have one, else you wouldn't have asked the
initial question. Only as recent as the last good backup.

1) 'dd'.
Pro: Great when you have a lot of files, a very full filesystem,
and you can afford the source to be readonly or offline during the copy.
Does special and sparse files great.
Con: Copies a lot of cruft if the filesystem isn't very full.
Doesn't let you bump the size of the filesystem. If filesystem is actively
changing, especially with new files being created and deleted, you just
copied garbage.

2) 'dump/restore'
Pro: Generally the most efficient filewise copy.
Usually does special and sparse files great.
Con: Becomes a multi-step or offlineprocess if the filesystem is fairly
active. dump/restore is not available for all filesystems.

3) 'cpio -p'
Pro: Almost as good as dump/restore on first copy. If your file modification
times are always increasing, it's very good at copying over updates.
Con: Various issues when directories are flagged as readonly.
Circumventable by doing directories after files.
Issues whe filesize changes, but mtime doesn't
Issues with special files.
Issues with sparse files.

4) 'rsync'
Pro: Handles special and sparse files. Handles when filesize changes
but mtime doesn't. Can do byte by byte compares of source and destination.
Con: Walks entire directory tree collecting stat(2) data, and sorts the
filelist prior to copying data.

5) Use a logical volume manager to migrate the logical volumes between
phyiscal folumes.
Pro: May be done online and duplicate copies of data exist for
very short periods of time.
Con: The last time I looked vinum was the LVMish tool for BSD and
it appeared too primitive for such operations. You've already
indicated that you are using standard partitions/slices.

5) Combinations of the above.

Anyhow, I look forward to your post on "How do I recover these files
I just destroyed that I didn't bother to back up."
--
Chris Dukes
< tajwerk> this job isnt bad though. Today we had free breakfast and
B0rg implants.
.

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