Setting nice and ionice for rsync via xinetd

Thanks to pointers by sr_, I seem to have a solution.

In /etc/xinet.d/rsync I added/changed these lines:

service rsync { ... nice = 19 server = /usr/bin/ionice server_args = -c 3 /usr/bin/rsync --daemon ... } 

To use ionice, I needed to change the server value to ionice instead of rsync. And then add rsync to the arguments section so that ionice launches it.

These snippet of Debian's /etc/default/rsync (Fedora probably doesn't divert too much),

# run rsyncd at a nice level? # ... RSYNC_NICE='' # run rsyncd with ionice? # ... # RSYNC_IONICE='-c3' 

makes me think that the *NICE values only affect the rsyncd daemon. Looking at /etc/init.d/rsync, we find

if [ -s $RSYNC_DEFAULTS_FILE ]; then . $RSYNC_DEFAULTS_FILE case "x$RSYNC_ENABLE" in xtrue|xfalse) ;; xinetd) exit 0 # ... the next lines examine the *NICE variables... 

i.e., if rsync is used with inetd, the *NICE values don't matter at all.

You could try replacing the rsync line in inetd.conf,

rsync stream tcp nowait root /usr/bin/rsync rsyncd --daemon ^^^^^^^^^^^^^^ 

with some command line setting your [io]nice values, I suppose.

Edit Scratch that last remark, you're using xinetd and thus, if you want to try it, have to change the rsync command in the snipped you included:

service rsync { ... server = /usr/bin/rsync ... } 

Edit2 Judging from this, there's a xinetd config item called nice for the niceness of the command:

nice Changes the server priority like the nice command does. 

So you could try a combination of setting nice=19 in /etc/xinetd.d/rsync and prepending the server command with some ionice call, e.g. ionice -c3.

(I'm not sure if this works, though. But if it doesn't, you can still run rsyncd as daemon and let the /etc/init.d script take care of everything.)