User guide

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3.4.4 NetApp Deduplication
NetApp deduplication saves space on primary storage by removing redundant copies of blocks within a volume
hosting hundreds of virtual desktops. This process is transparent to the application and user and can be enabled
and disabled on the fly. In a Citrix XenDesktop environment, deduplication provides significant space savings,
given that each virtual machine is an identical copy of the OS, applications, and patches. The savings are also
achieved for the user data hosted on CIFS home directories. For more information on NetApp deduplication, refer
to NetApp TR-3505: NetApp Deduplication for FAS, Deployment and Implementation Guide.
Figure 25. NetApp Deduplication
Using NetApp deduplication and file FlexClone not only can reduce the overall storage footprint of Citrix
XenDesktop desktops but also can improve performance by using transparent storage cache sharing. Data that is
deduplicated or nonduplicated, in the case of file FlexClone data, on disk will only exist in storage array cache
once per volume. All subsequent reads from any of the virtual machine disks of a block that is already in cache
will be read from cache and not from disk, therefore improving performance by 10x. Any nondeduplicated data
that is not in cache must be read from disk. Data that is deduplicated but does not have as many block references
as a heavily deduped data will appear in cache only once but based on the frequency of access might be evicted
earlier than data that has many references or is heavily used.
Figure 26. NetApp Deduplication and Flexcone
Before AfterBefore After