This is all contained in the Zenoss Upgrade guide.

Attach to Zope

serviced service attach zope/0
su zenoss

You can run the following commands to check on zenoss

zenossdbpack
findposkeyerror
zenrelationscan
zencatalogscan

zenossdbpack : Quickly scans the Zope Object Database (ZODB) to provide a preliminary indication of the health of the database, and to determine whether the database needs to be compressed with “zenossdbpack” before upgrading.
findposkeyerror : Checks objects and their relationships, and provides options for fixing errors.
zenrelationscan : Checks only ZenRelations between objects.
zencatalogscan : Checks ZODB object catalogs, which speed up web interface access