Setup Guide

56 Best Practices
Adjusting SCSI Timeouts for the PowerVault MD3000i Storage Arrays
If the XenServer host is connected to the PowerVault MD3000i storage arrays,
on the XenServer host, you can change the SCSI timeout value for the SCSI
device(s) on the PowerVault MD3000i storage arrays. Follow the steps below:
1
Create a new udev rule file with name 96-md3000i-sto.rules at
/etc/udev/rules.d/
and add the following text:
KERNEL=="sd*[!0-9]", ACTION=="add", SYSFS{model}==
"MD3000i", SYSFS{vendor}=="DELL", RUN+="/bin/sh -c
'echo 200 > /sys$DEVPATH/device/timeout'"
2
Save the file. Attach the iSCSI volume to the XenServer host and create an
SR.
3 Adjust the SCSI timeout on the Windows VMs residing on the SR
resident on the PowerVault MD3000i by changing the following registry
setting:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\dis
k\TimeOutValue.
4 Create the value if it is not present. Set this value to 200 .
NOTE: Do not modify the SCSI timeout in the paravirtualized Linux VMs as the
VM virtual disks are not presented as SCSI disks.
Using an iSCSI initiator inside a VM is the same as using an iSCSI initiator in
a physical system. For specific steps to install the relevant Dell multi-pathing
drivers and supported iSCSI initiators, and to attach the PowerVault
MD3000i volumes to a VM using the iSCSI initiator inside the VM, see the
MD3000i Systems Installation Guide available on the Dell Support website at
support.dell.com/manuals. There are no extra steps required to modify the
SCSI timeouts when Dell multi-pathing drivers control the LUN(s) on a
PowerVault MD3000i array.
Configuring XenServer Management Network for
High Availability
For detailed instructions on configuring XenServer management network for
HA, see the “Creating NIC Bonds” section of the XenServer Administrator’s
Guide available on the Citrix XenServer Dell Edition website at
citrix.com/xenserver/dell.