[clug] fastest way to copy a fs
robert at apex.net.au
Thu Jan 18 23:17:56 GMT 2007
Surely the fastest way to copy a file system is to use dd on the raw
device. Of course, the target partition has to be larger than the source
and if it isn't exactly the same size, you'll have to do a resize after.
Peter Barker wrote:
> On Fri, 19 Jan 2007, Tony and Robyn Lewis wrote:
>> I'm not sure this is going to save you anything. Each run of rsync is
>> going to completely read both source and dest, in order to checksum
>> all the chunks. So unless your reads are significantly faster than
>> your writes, you're not going to save anything in your downtime.
>> I could be wrong though...
> Slightly. By default rsync doesn't checksum all files on a re-sync. It
> will compare dates-and-times and size first, and if they haven't
> changed, assume the content hasn't changed either. See the --checksum
> You still have to traverse the filing system, though, and that's kind of
> One option which hasn't been discussed is snapshotting. I've never
> played with it (just one of a million interesting things...), but would
> it be possible to:
> a) snapshot, sync the snapshot followed by
> b) generate diffs between the snapshot and the current state of the fs
> c) copy the diffs to the snapshot to the machine holding the copy and then
> d) apply those to the copy-of-the-snapshot.
> As I said, I've never played with snapshotting, and I wouldn't have
> /thought/ the fs would bear the changes-to-the-snapshot information to
> the user. Just a thought.
If the Hunter S Thomson quote "When the going gets weird, the weird turn
pro" is true, why aren't I rich?
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