Inotify and rsync on large number of files

inotifyrsync

I am using inotify to watch a directory and sync files between servers using rsync. Syncing works perfectly, and memory usage is mostly not an issue. However, recently a large number of files were added (350k) and this has impacted performance, specifically on CPU. Now when rsync runs, CPU usage spikes to 90%/100% and rsync takes long to complete, there are 650k files being watched/synced.

Is there any way to speed up rsync and only rsync the directory that has been changed? Or alternatively to set up multiple inotifywaits on separate directories. Script being used is below.

UPDATE: I have added the –update flag and usage seems mostly unchanged

#! /bin/bash

EVENTS="CREATE,DELETE,MODIFY,MOVED_FROM,MOVED_TO"

inotifywait -e "$EVENTS" -m -r --format '%:e %f' /var/www/ --exclude '/var/www/.*cache.*' | (
WAITING="";
while true; do
    LINE="";
    read -t 1 LINE;
    if test -z "$LINE"; then
        if test ! -z "$WAITING"; then
                echo "CHANGE";
                WAITING="";
                rsync --update -alvzr --exclude '*cache*' --exclude '*.git*' /var/www/* root@secondwebserver:/var/www/
        fi;
    else
        WAITING=1;
    fi;
done)

Best Answer

I ended up removing the compression option (z) and upping the WAITING var to 10 (seconds). This seems to have helped, rsync still spikes CPU load but it is shorter lived. Credit goes to an answer on unix stackexchange

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