Hi, when using RSync for mirroring, the checksums of a file are calculated for each transfer. But that causes a lot of CPU/IO load on the server machine and degrades throughput even if there's plenty of network bandwidth. So I want to propose a pre-calculating feature for checksums.
The easiest way would be to add a CLI-option like '--pre-checksum' to RSync. That way RSync would just calculate the checksums per file and per blocks and store them in (a) cache file(s) in non-daemon mode. In daemon mode RSync would just look for that cache file(s) to avoid superfluous load recalculating the checksums on each transfer. Pre-calculating the checksums could also be set in the RSync config file to make the RSync daemon calculating the checksums only once. That would also allow to use a weak machine as mirror server an pre-calculate the checksums on another machine (I use RSync on a home router with an fullspeed USB disk and files of 2 GByte size - calculating the checksums consumes hours without any transfer and I don't wan't to keep a standard PC running 24h hours a day because of power consumption. But that PC could easily do checksum pre-calculation before moving the files to the home router/USB-disk combo). But anyway, RSync is a great tool! ;) Thanx Renne -- Please use reply-all for most replies to avoid omitting the mailing list. To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
