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music-mirror/tools
Emma Thorpe d6ef70922c
Build and publish container / build (pull_request) Successful in 2m39s
perf: cut round trips over a network mount, and allow skipping the count
The transfer is metadata-bound rather than throughput-bound. Fifty thousand
files is fifty thousand round trips, and the counting pass added for the
percentage doubles that.

--whole-file is already implied when both ends are local paths, which an SMB or
FAT mount is, but stating it records that the delta algorithm is deliberately
unwanted here: it would read every destination file back over USB to checksum
it, in order to avoid resending an MP3 that has changed in its entirety anyway.

--omit-dir-times drops one setattr per directory. Across six thousand album
folders on a FAT card that is six thousand operations spent on timestamps
nothing reads.

-Q skips the counting pass. The percentage and the estimate are worth a second
walk of a local tree and frequently are not worth one of a network mount, so
that is now a choice rather than a fixed cost.

The README covers the part that is not an rsync flag at all: SMB defaults to a
one second attribute cache, so nearly every stat goes to the wire, twice. An
actimeo of sixty on the mount does more than any of the above, and closes most
of the gap that would otherwise argue for moving to NFS.
2026-08-25 12:44:53 +01:00
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