Setup Guide

74 Best Practices
Adjusting SCSI Timeouts for PowerVault MD3000i Storage Arrays
If the XenServer host is connected to PowerVault MD3000i storage arrays, on
the XenServer host, change the SCSI timeout value for the SCSI device(s) on
the PowerVault MD3000i storage arrays. 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'"
Save the file. Attach the iSCSI volume to the XenServer host and create an
SR.
Adjust the SCSI timeout on Windows VMs residing on the SR resident on
MD3000i by changing the following registry setting:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\disk\T
imeOutValue.
The value needs to be created if not present. Set this value to 200.
Do not modify the SCSI timeout in 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 relevant Dell multi-pathing
drivers and supported iSCSI initiators, and to attach 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. There are no extra steps required to modify SCSI timeouts
when Dell multi-pathing drivers control the LUN(s) on an 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.