Change the Outstanding IO Requests Setting

If you adjusted the LUN queue depth, change the Disk.SchedNumReqOutstanding (DSNRO) parameter, so that its value matches the queue depth. The parameter controls the maximum number of outstanding IO requests that all virtual machines can issue to the LUN.

Change this parameter only when you have multiple virtual machines active on a LUN. The parameter does not apply when only one virtual machine is active. In that case, the bandwidth is controlled by the queue depth of the storage adapter.

The parameter is set per device.

Procedure

1. Enter the following command to display the current DSNRO setting for the specified device:
   esxcli storage core device list -d device_ID
   You get the output similar to the following:

     No of outstanding IOs with competing worlds: 32

2. Change the DSNRO value by entering the following command:
   esxcli storage core device set -O | --sched-num-req-outstanding value -d device_ID
3. Verify your changes by entering the following command:
   esxcli storage core device list -d device_ID