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Steven J Gold wrote:... I expected QRecall to capture it as a new volume but since its contents are almost completely identical to the prior replaced volume, I expected the Capture to find 99% of the data already in the archive (it turned out to be 98.69%) and complete very rapidly.
So I was surprised when it took over 4 hours to capture 167.7GB since it actually only needed to write 1.53GB.
Most surprising was the variance in speed it reported. Sometimes it reported "1.63GB per second", but sometimes only "7.28 *MB* per second" -- that's quite a magnitude variance(!). The average rate was 687 MB/min. I'm curious why it sometimes dipped into the single MB/sec digits.
Steven J Gold wrote:BTW, does the existing quanta need to be decompressed for the comparison, or does the comparison operate on the compressed data?
I guess I'm asking if the de-duplication process is slower if the archive is compressed?
Steven J Gold wrote:Remember RAM Doubler from Connectix back in the 90's?
Connectix's patents on memory compression expired, and recently Apple used stuff from them to implement Memory Compression in what, Yosemite?, because it was faster to compress memory than to swap it to disk.
I actually found that the fastest way to move a large file (40+ GB) file from a USB-2 connected disk to my laptop is to Restore it from a QRecall archive to the target disk rather than do a straight copy. I assume this is because the archive is compressed and thereby takes fewer I/O operations to "read" the file than to do a Finder copy from the external disk?
(I would never have guessed I'd use QRecall as a "faster than Finder file copier" )