Anti-virus tool on SQL Server
Another common question in the forums asking about what are the best practices for using antivirus software on servers running SQL Server.
In my experience if your SQL Server is not a internet-faced one then no need to have one installed on a SQL Server that is dedicated to databases, rather tighten the access on the file access and share on the Operating System. If the server resource is really high then to some extent, the usual recommendation is to set exclusions for the SQL data and log files, and any backups.
I would like refere KBA309422 that has useful information about the antivirus.
Further I would suggest to monitor the CPU & I/O utilization when an Anti-virus tools is installed, also it is required for monitoring purpose even though if you haven't installed one. This is a foremost option to have such information if have complaints about SQL Server performance.
So if that SQL Server is a dedicated server then no worries the security can be tightened using Roles & privileges on SQL Server, also it is better to restrict any sort of file sharing on O/S. If there is such requirement and having SQL Cluster equipped then besides excluding all SQL Server and Analysis Services file types such as .mdf, .nfg, and .ldf, you must exclude the MSCS directory on the quorum drive as well. It is especially important in a clustered configuration to exclude the SQL Server files. Otherwise the Anti-virus will hinder the time to failover in case of any issues during the switch over of resources from one node to another, don't forget to include same set of action on another node.
I haven't seen any such anti-virus software that is a cluster-aware! In my experience it can have strange effects and interact in a negative way with clusters. If it is compulsory to have Anti-virus installed on your environment then be sure to check with your antivirus vendor to see if it is cluster-aware or not.
In any case having the control of resource usage with PERFMON and PROFILER for SQL Server will give you more advantage to get to the root cause of a performance issue.