ZFS sizing issue. The current zfs is 200 cylinders which to date is still not enough. We currently do not connect to many of the cics regions and if this goes forward, the more regions connected to would increase the log activity significantly.
PTF Y83629A - for AppMon 5.5 reduces the severity of these messages from info to fine to avoid creating them in normal operation. This would significantly reduce the volume of log traffic from your USS agents.