CPU Co-Stop

David Klee discusses an important hypervisor-level metric:

VMware’s CPU Co-Stop metric shows you the amount of time that a parallelized request spends trying to line up the vCPU schedulers for the simultaneous execution of a task on multiple vCPUs. It’s measured in milliseconds spent in the queue per vCPU per polling interval. Higher is bad. Very bad. The operating system is constantly reviewing the running processes, and checking their runtime states. It can detect that a CPU isn’t keeping up with the others, and might actually flag a CPU is actually BAD if it can’t keep up and the difference is too great.

This is extremely useful information for DBAs in virtualized environments.  My crude and overly simplistic answer is, don’t over-book vCPUs on hosts running important VMs like your SQL Server instances.

Related Posts

Finding Windows Version With T-SQL

Jack Vamvas shows us several methods to figure out which version of Windows you have installed from within SQL Server: Method 2 : Use xp_cmdshell – although this does mean enabling xp_cmdshell , which is in many organisations as security violation  exec master..xp_cmdshell 'systeminfo' Click through for several less controversial methods.

Read More

Azure SQL Database and Extended Events

Dave Bland shows how to set up and read an extended event file on Azure SQL Database: This first step when using T-SQL to read Extended Files that are stored in an Azure Storage Account is to create a database credential.  Of course the credential will provide essential security information to connect to the Azure […]

Read More

Categories

March 2016
MTWTFSS
« Feb Apr »
 123456
78910111213
14151617181920
21222324252627
28293031