copying milllions of small files and millions of dirs
cswiger at mac.com
Thu Aug 15 19:26:26 UTC 2013
On Aug 15, 2013, at 11:13 AM, aurfalien <aurfalien at gmail.com> wrote:
> Is there a faster way to copy files over NFS?
> Currently breaking up a simple rsync over 7 or so scripts which copies 22 dirs having ~500,000 dirs or files each.
There's a maximum useful concurrency which depends on how many disk spindles and what flavor of RAID is in use; exceeding it will result in thrashing the disks and heavily reducing throughput due to competing I/O requests. Try measuring aggregate performance when running fewer rsyncs at once and see whether it improves.
Of course, putting half a million files into a single directory level is also a bad idea, even with dirhash support. You'd do better to break them up into subdirs containing fewer than ~10K files apiece.
> Obviously reading all the meta data is a PITA.
> Doin 10Gb/jumbos but in this case it don't make much of a hoot of a diff.
Yeah, probably not-- you're almost certainly I/O bound, not network bound.
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