White Papers

BP1018 Sizing and Best Practices for Citrix XenDesktop with Dell EqualLogic Storage 36
7 Best practices
7.1 Desktop profiles and I/O storms
7.1.1 Implement roaming profiles and folder redirection
Using a separate storage array and redirecting user profile/folders to a file server using that array is
highly recommended for better management and increased performance of VDI environments.
Implementing roaming profiles and folder redirection helped in reducing the performance impact
during user logon and also allowed user data to be persistent across boot. More information related
folder redirection and roaming profiles can be found in Appendix B
7.1.2 Use XenDesktop Power management feature
Citrix XenDesktop has a feature called Power Management that can be used to maintain the required
number of idle virtual desktops based on user logins.
By default, the Power management feature will ensure that 10% of the total number of desktops are
available. It is recommended to set the Power Management feature to 100% so that all the virtual
desktops are pre-booted. This will result in reduced login time and better user experience. However it
may not be always possible to pre-boot 100% of the virtual desktops due to resource or power
constraints in a data center. In these scenarios, we recommend pre-booting as many desktops as
possible just before users start logging in to the virtual desktops.
7.1.3 Boot and login storm considerations
To avoid I/O bursts due to boot storms, we recommend pre-booting all virtual desktops before the
first set of users start logging on at the beginning of a workday. It may not be possible to pre-boot all
virtual desktops due to infrastructure limitations. In this case, we recommend pre-booting as many
desktops as possible to minimize desktop boot time and improve user experience.
If the storage layer is designed based only on the steady state IOPS, the user will experience degraded
performance during the duration of the login storm. We recommend designing the storage after
considering the boot and login storms.
Based on our test results, VDI workload using provisioning servers is highly write-intensive (90% write
and 10% read I/O). Because of this, using SSD drives will greatly improve the performance. You also
need sufficient capacity on the array to host write cache for the virtual desktops. We recommend
PS6010XVS hybrid arrays because they offer the right combination of performance and capacity
suitable for VDI environments.
7.2 ESXi host configuration
We recommend implementing the following recommendations on all ESXi servers hosting virtual
desktops and Citrix infrastructure:
- Install and configure EqualLogic Multipathing Extension Module (MEM) for vSphere 4.1
- Separate the virtual switch to segregate iSCSI SAN traffic, VDI traffic, and
Management/Infrastructure network I/O
- Every network path on the servers must be assigned at least two NICs for high availability.