Strange CPU spikes in system time on smbd
Since updating, we have a server that's having weird intermittent CPU spikes, seemingly in smbd (it monopolizes 40-50% of the CPU time while doing so). What's weird is other servers, configured similarly and at similar OI revisions, don't seem to exhibit this. When this happens, smbd seems to be hitting /var/krb5/rcache/root/cifs_0 a lot (observed via zfsslower, where it's being serviced entirely from ARC).
I'm linking to a flame graph captured via profile-299 when these spikes happen (kernel stacks), with the unix`idle derived stacks removed:
I tried to attach the output of smbsrv.d during this time (fairly large), but even with xz it's still 4.6 MB (just slightly too large).