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BP1018 Sizing and Best Practices for Citrix XenDesktop with Dell EqualLogic Storage 6
• vDisk was configured using standard mode and it was made read-only so that the two
provisioning servers can access it simultaneously.
• Any modifications made to the streamed image by the virtual desktop were stored in the write
cache. Each virtual desktop consumed 3 GB of storage capacity – 2 GB of write cache (that
includes 1 GB page file) and 1 GB of RAM. The “Cache on Device Hard Drive” option provided
by Citrix Provisioning Services was used to mount the write cache.
• A CIFS share through a Microsoft® Windows® file server virtual machine was created using a 2
TB volume hosted on a Dell EqualLogic PS6510E array. All the user folders and user shares that
contain user or application data from virtual desktops were stored on the CIFS share.
• A total of 32 Windows Server 2008 R2 virtual machines were hosted on three ESXi servers for
Login VSI load generation. Each virtual machine was used as a Login VSI launcher and each
launcher invoked 40 sessions.
The core infrastructure components are listed below.
Table 1 Citrix XenDesktop core infrastructure components
Citrix XenDesktop infrastructure
Component Description
Citrix Web Interface
Provides the user interface to the XenDesktop VDI environment.
Citrix License servers Manages Citrix licences for XenDesktop environment.
Active Directory Common namespace and secured access to all the servers and VMs in
the environment.
DHCP Used to provide IP address for virtual desktops.
DNS IP address and host name resolution for the entire XenDesktop
environment.
Microsoft® SQL Server® Microsoft SQL Server database was used to create databases for Citrix
PVS, DDC, and VMware® vCenter® server.
Citrix Provisioning Services
Servers (PVS)
Creates and provisions virtual desktops from a single desktop image
on demand. Provides great flexibility, simplifies management of
desktop images, and ensures that each user gets a pristine virtual
desktop every time they log on.
Desktop Delivery
Controllers (DDC)
Manages the virtual desktop requirements of the user. Authenticates
users by interacting with Active Directory. Manages the connectivity
between users and their virtual desktops.
Virtual Desktop Agent
(VDA)
Installed on virtual desktops. Manages the direct connection between
virtual desktops and client devices.
Independent Computing
Architecture (ICA)
A proprietary protocol designed by Citrix. Used for communication
between client devices and virtual desktops.
Virtual desktop storage configuration
Component
Description
PVS vDisk The disk image files located on provisioning servers to boot the virtual
desktops. These are configured on shared EqualLogic storage hosted
by PVS servers.
PVS write cache Any writes made to the desktop OS are redirected to a temporary area
called the write cache. The write cache is configured as a virtual
desktop hard drive, which is physically located on the shared
EqualLogic storage via ESXi datastores.
User Data (CIFS Share) The user data for each virtual desktop is mounted from a NAS file
server using shared storage.
Hypervisor