The upper-limit control for a volume is a suitable solution if you want to suppress influences on other services when unexpected massive I/O requests are issued by a specific service. On the other hand, the upper-limit control for a QoS group is a suitable solution to suppress influences on other tenants when unexpected massive I/O requests are issued by a tenant that handles multiple services. Configure the upper limit setting for a volume or a Qos group depending on the use case.
Upper-limit value setting
If you set an upper-limit value that is lower than the actual throughput, the application might be drastically slowed down. For the initial upper-limit value, specify the value with a margin, based on the amount of throughput during your business cycle (for example, one day to one week).
For details about the amount of throughput, see the server's throughput data or the performance values obtained by using Export Tool 2 or the System Monitor in VSP One Block Administrator.
When an upper-limit alert is issued
If an upper-limit alert is issued or the monitor information is abnormal during operations, an unexpectedly large amount of I/O requests might be issued. Use the QoS monitor function to check the amount of throughput, and revise the upper-limit value, if necessary.