A very interesting feature of SQL Server is the Resource Govenor; Resource Governor is a feature which can manage SQL Server Workload and System Resource Consumption. It is available since SQL server 2008 (Enterprise), and was fully described many years ago by my partner in crime & SQL Server MVP Isabelle Van Campenhoudt. We had an “accidental “ talk on SQL Server 2014 and she mentioned the new IOPS throttling feature that I will quickly describe here.
Until SQL Server 2014, what we could do was setting thresholds on CPU and Memory.
For more details on how to user the SQL Server resource Governor to limit CPU & Memory usage during crawling operation, read the excellent post of Wictor Wilen .
Wictor details how to throttle during (work hours) CPU and memory on operations running on the SharePoint crawling database.
However one of the new feature of SQL Server 2014 Enterprise is throttling IOPS, which can also be applied not just to crawling operations, but also to regular DBCC CHECKDB operations: Indeed, it is usually considered as a good practice to regularly check the integrity of your SharePoint databases by using the DBCC CHECDB SQL server instruction.
More specifically resource pools now support configuration of minimum and maximum IOPS per volume in addition to CPU/Memory settings enabling more comprehensive resource isolation controls.
Read the following post.
I still have to upgrade my existing SharePoint farms to SQL Server 2014 (supported with the SharePoint 2013 April 2014 CU, more info here).