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In a virtual server environment, IT managers
need to pay careful attention to the
impact that Wide Area Network
(WAN) performance has on application
performance. When virtual servers are
placed in centralized locations, limited
bandwidth, high latency, and packet loss
on the WAN can impact application
performance for end users. At the same
time, the WAN can present a major
obstacle for data protection and disaster
recovery in these environments when large
virtual images must be replicated between
geographically disperse locations.
Server Consolidation
Virtual machines suffer all the same
performance challenges as physical
servers when accessed across a WAN.
More specifically, WAN bandwidth, latency and packet loss can all adversely impact the
performance of centrally hosted virtual
servers. Because Silver Peak is application agnostic and completely transparent to end devices, Silver Peak's Network Acceleration, Network Integrity, and Network Memory accelerate the performance of all centralized servers in the same way , whether virtual or physical.
Disaster Recovery
Many enterprises maintain duplicate or backup data centers and use virtual images for all mission critical servers as part of a disaster recovery strategy. System snapshots are taken using virtual server software, such as VMware. The system image can then be loaded back onto an identical or similar system in the backup data center to create an exact duplicate of that system.
Virtual images are typically 500MB to Gigabytes in size, so transferring these images for many servers can be time consuming and prone to time-out errors. Even when compressed, virtual images can take up considerable bandwidth. In addition, data backup and disaster recovery can be adversely affected by latency over a WAN, particularly when using TCP. Even expensive, high bandwidth links can have difficulty supporting virtual image transfers.
Silver Peak’s NX appliances dramatically reduce the time to backup virtual server images between disaster recovery locations.This is due to the advanced data reduction capabilities inherent to Network Memory, coupled with additional compression techniques within the Silver Peak solution.
The graph below shows a typical customer example, with Silver Peak providing a 60x improvement in VMware transfer times - from one hour to 1 minute when using a pre-compressed file.

When using uncompressed VMware images, 10x performance improvements can also be experienced on the initial image transfer.

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