Well, get that problem today.
Commandline test shows me, that problem caused by creation of log and file after tar command run.
Not sure is that because multicores, or just tar version updated (yesterday it was fine, but today failed on all vsites).
Fixed with change
$backup_cmd = "$cmd_tar --ignore-failed-read --create --directory=$dmn_dir --$zip --file=$dmn_dir/$backup_filename --exclude=logs --exclude=phptmp --exclude=backups --exclude=$backup_filename --exclude=$backup_filename.log . 2> $dmn_dir/$backup_filename.log 1>&2";
to
$backup_cmd = "touch $dmn_dir/$backup_filename $dmn_dir/$backup_filename.log && $cmd_tar --ignore-failed-read --create --directory=$dmn_dir --$zip --file=$dmn_dir/$backup_filename --exclude=logs --exclude=phptmp --exclude=backups --exclude=$backup_filename --exclude=$backup_filename.log . 2> $dmn_dir/$backup_filename.log 1>&2";
-- i have added touch command BEFORE running tar -- so content of directory remains static.
Also, to have backup uploaded to external FTP, instead of cron i have added hook after call to backup_all_shut_down -- so backup gets sync as soon as backup finished.
http://www.isp-control.net/documentation...ftp_backup