XenServer to repartition host memory dynamically in response to changing numbers of guests, or changing host memory pressure. XenServer chooses a target from within the range and adjusts the guest's memory allocation to meet the target.

Note:

It is possible to change between target mode and dynamic range mode at any time for any running guest. Simply specify a new target, or a new dynamic range, and XenServer takes care of the rest.

Memory Constraints

XenServer allows administrators to use all memory control operations with any guest operating system. However, XenServer enforces the following memory property ordering constraint for all guests:

0 memory-static-min memory-dynamic-min memory-dynamic-max memory- static-max

XenServer allows administrators to change guest memory properties to any values that satisfy this constraint, subject to validation checks. However, in addition to the above constraint, Citrix supports only certain guest memory configurations for each supported operating system. See below for further details.

Supported Operating Systems

Citrix supports only certain guest memory configurations. The range of supported configurations depends on the guest operating system in use. XenServer does not prevent administrators from configuring guests to exceed the supported limit. However, customers are strongly advised to keep memory properties within the supported limits to avoid performance or stability problems.

Operating System

 

 

 

Supported Memory Limits

 

 

 

 

 

 

 

 

 

 

 

Family

Version

 

Architectures

Dynamic

Dynamic

Additional

 

 

 

 

 

Minimum

Maximum

Constraints

 

 

 

 

 

 

 

Microsoft Windows

XP SP3

 

x86

256 MB

4 GB

Dynamic Minimum

 

 

 

 

 

 

¼

Static

Maximum

 

Server

2003

x86

 

 

 

256 MB

64 GB

for

all

supported

 

(+SP1,SP2)

 

 

 

operating systems

 

x64

256 MB

128 GB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Server

2008

x86

512 MB

64 GB

 

 

 

 

(+SP2)

 

 

 

 

 

 

 

 

 

 

x64

512 MB

128 GB

 

 

 

 

 

 

 

 

 

 

 

 

 

Server

2008 R2

x64

512 MB

128 GB

 

 

 

 

(+SP1)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vista (+SP1,SP2)

x86

1 GB

4 GB

 

 

 

 

 

 

 

 

 

 

 

 

7 (+SP1)

x86

1 GB

4 GB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

x64

2 GB

128 GB

 

 

 

 

 

 

 

 

 

 

 

Cent0S Linux

4.5 - 4.8

x86

256 MB

16 GB

 

 

 

 

 

 

 

 

 

 

 

 

5.0 - 5.6

x86 x64

512 MB

16 GB

 

 

 

 

 

 

 

 

 

 

 

 

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Citrix Systems 6 manual Memory Constraints, Supported Operating Systems, Operating System Supported Memory Limits