Adding a delay when restarting all OSDs on a host

[Wido den Hollander <wido@42on.com>]

Hi,

Currently on Ubuntu with Upstart when you invoke a restart like this:

$ sudo restart ceph-osd-all

It will restart all OSDs at once, which can increase the load on the 
system a quite a bit.

It's better to restart all OSDs by restarting them one by one:

$ sudo ceph restart ceph-osd id=X

But you then have to figure out all the IDs by doing a find in 
/var/lib/ceph/osd and that's more manual work.

I'm thinking of patching the init scripts which allows something like this:

$ sudo restart ceph-osd-all delay=180

It then waits 180 seconds between each OSD restart making the proces 
even smoother.

I know there are currently sysvinit, upstart and systemd scripts, so it 
has to be implemented on various places, but how does the general idea 
sound?

-- 
Wido den Hollander
Ceph consultant and trainer
42on B.V.

Phone: +31 (0)20 700 9902
Skype: contact42on