rsync --inplace not reading target file?

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http://serverfault.com – I'm trying to optimize the daily backup of a LVM snapshot of a large MySQL database. It works quite ok when I just cp the files (local RAID to other local RAID), with an average speed of ~100MB/s. But since the database files (600GB, most of it in two files of 350GB and 250GB) do not change very much over the course of one day, I thought it would be more efficient to only copy the changed blocks. I'm using rsync --safe-links --inplace -crptogx -B 8388608 /source/ /destination/ It did work, was slower than the simple copy, and I did not see any read activity on the target disk. My thought w (HowTos)