Error 823 and no connection

One of our servers tells us it has Error 823 issues: > TITLE: Connect to Server > > Cannot connect to ServerName. > ADDITIONAL INFORMATION: Warning: Fatal error 823 occurred at Mar 1 2016 > > 10:45AM. Note the error and time, > and contact your system administrator. (Microsoft SQL Server, Error: > 21) The windows log is floated with the same message. No connection to the sql server is possible. So DBCC CHECKDB cannot be used / executed. I ran SQLIOSIM and it raised couple of errors that requests are outstanding for more than n sec on a specific drive. A Similar issue happened last night on another system - and it looks like it was workarounded by a failover. I don't know where to look at next since I cant even connect to the Sql Server.