Your messages actually look a lot like the messages we receive from our SAN during a backup, that may be something to check if there are SAN backups occurring they will freeze the I/O and do a reset to Device. We don't have that anymore after changing to Avamar backups. Those messages could also indicate SAN disk pressure, I have seen that in the past as well, but I would definitely see if it correlates to some kind of SAN backup.