While trying to investigate some performance issues with our SQL Server database, I've noticed our wait statistics seem high for ASYNC_IO_COMPLETION and PAGEIOLATCH_*. In Resource Monitor I noticed that tempDB is frequently (at least 1 time per hour) Reading/Writing large amounts of data, Total (B/Sec) range from 5GB - 25GB.
The tempDB is on a separate Virtual Disk than the Database and Log Files. TempDB size is 4 GB. Our main DB and Log file is 40GB in size each. I've tried researching perfmon counters for this but haven't been able to find anything I can make sense of in order to figure out why I'm getting certain numbers.
Is it unusual that the total data for tempDB is so high through resource monitor? Our main Database is only growing about 50MB per day. What should I be looking for to figure out what is causing such high data on tempDB and if this is causing an I/O Bottleneck? If the best method is by using specific perfmon counters, which counters should I be looking at and what values are good or bad?