I just recently updated from Plesk 9 to Plesk 9.0.1 since a lot of updates were applied to the bundled software, such as AtMail. I then SSH’d into my server and found several /usr/bin/sw-cp-server processes running. I wondered, what are these and why are there so many of them running?

Turns out that there was a main process that was running (/usr/sbin/sw-cp-serverd -f /etc/sw-cp-server/config) and it allows Plesk to run. Looks like they changed the name of the service on the Plesk 9 update:

[root@yourserver]service psa status
sw-cp-serverd (pid 10216) is running… (brand new name)

The other processes that were running were running out of the ’sso’ user (I don’t remember the path to the process ). Running a search for this user on the passwd file shows the following:

[root@yourserver]cat /etc/passwd | grep sso
sso:x:112:101: Parallels SSO system user:/var/lib/sso:/bin/false

Turns out that SSO stands for Single Sign-On, a feature that allows you to sign into multiple Parallels products under a single login.

I don’t have a need for this, and a restart of the sw-cp-serverd service cleared these processes up.

If you want more information about setting up SSO, take a look at http://forum.parallels.com/showthread.php?t=84097 – it seems to have some helpful information.