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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
Minimum
Dynamic
Maximum
Additional
Constraints
XP SP3 x86 ≥ 256 MB ≤ 4 GB
x86 ≥ 256 MB ≤ 64 GB
Server 2003
(+SP1,SP2)
x64 ≥ 256 MB ≤ 128 GB
x86 ≥ 512 MB ≤ 64 GB
Server 2008
(+SP2)
x64 ≥ 512 MB ≤ 128 GB
Server 2008 R2
(+SP1)
x64 ≥ 512 MB ≤ 128 GB
Vista (+SP1,SP2) x86 ≥ 1 GB ≤ 4 GB
x86 ≥ 1 GB ≤ 4 GB
Microsoft Windows
7 (+SP1)
x64 ≥ 2 GB ≤ 128 GB
4.5 - 4.8 x86 ≥ 256 MB ≤ 16 GB
Cent0S Linux
5.0 - 5.6 x86 x64 ≥ 512 MB ≤ 16 GB
Dynamic Minimum ≥
¼ Static Maximum
for all supported
operating systems