Dec 12 20:57:36 lb-A err statsd[6711]: 011b0203:3:
Error ‘No such file or directory’ opening file /sys/block/sdb/stat
Dec 12 20:57:36 lb-A err statsd[6711]: 011b0900:3:
TMSTAT error max disk stat: read failed.
The error is because the F5 is trying to query for stats from a removed hard drive or USB. Bugid 441400 is associated with this error. This has been fixed post 11.6 code version and for older code versions, reboot fixes this error.