My vdsm log files are huge:

-rw-r--r--  1 vdsm kvm  1.8G Nov 22 11:32 vdsm.log

And this is juste half an hour of logs:

$ head -1 vdsm.log
2018-11-22 11:01:12,132+0100 ERROR (mailbox-spm) [storage.MailBox.SpmMailMonitor] mailbox 2 checksum failed, not clearing mailbox, clearing new mail (data='...lots of data', expected='\xa4\x06\x08\x00') (mailbox:612)

I just upgraded vdsm:
$ rpm -qi vdsm
Name        : vdsm
Version     : 4.20.43