Setting nice and ionice for rsync via xinetd

Question

I am attempting to set nice and ionice for rsync via xinetd. I am running Fedora 16. The reason I would like to use these values is to reduce the rsync process to an idle state so other processes run unaffected.

I have tried to use /etc/default/rsync to set nice and ionice values, but it looks like these are not working for me. The rsync process is always started with a nice value of 0, even when I set it to 19. Do these settings work in xinetd? Is there another way to nice rsync via xinetd?

Here are my config files:

/etc/rsync.conf:

log file = /var/log/rsyncd.log
pid file = /var/run/rsyncd.pid
lock file = /var/run/rsync.lock
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/etc/xinetd.d/rsync:

service rsync
{
    disable = no
    flags           = IPv6
    socket_type     = stream
    wait            = no
    user            = root
    server          = /usr/bin/rsync
    server_args     = --daemon
    log_on_failure  += USERID
}

/etc/default/rsync:

RSYNC_ENABLE=inetd
RSYNC_OPTS=''
RSYNC_NICE='19'
RSYNC_IONICE='-c3'

score 3 · Answer 1 · answered Feb 17 '12 at 09:52

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.

sr_ · Answer 2 · 2012-02-05T13:09:44.940

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.)

Setting nice and ionice for rsync via xinetd

2 Answers2