Xen 4.2 Limits: Difference between revisions
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| #REDIRECT [[Xen_Release_Features]] | |||
| {{TODO|This is a work in progress. Feel free to add requests for more to the talk page or add additional information here}} | |||
| This document contains information about limits of Xen 4.2. | |||
| == CPUs & Memory == | |||
| * Xen can scale up to 4,095 host CPUs with 5Tb of RAM.  | |||
| * Using Para Virtualization (PV), Xen supports a maximum of 512 VCPUs with 512Gb RAM per guest.  | |||
| * Using Hardware Virtualization (HVM), Xen supports a maximum of 128 VCPUs with 512Gb RAM per guest. | |||
| Note that in theory Xen supports 8192 VCPUs, but event channel limitations (4k per guest) make it impossible for a guest this huge to | |||
| boot, as each vCPU is expected to minimally require 2 of them (timer vIRQ and IPIs). The limits stated above, are limits that have been tested. However, it is possibly to exceed these in theory. | |||
| == Other Limits == | |||
| * Maximum of 32K interrupts and 2k PCI segments: this limits the number of devices that can be used in two ways:  | |||
| ** The number of devices many can be attached to the system must fit into 2k PCI segments, i.e. 2k * 256 [buses] * 32 [devices] * 8 [functions]) | |||
| ** The number of hardware interrupts they may surface (one would expect at least one interrupt per device function, so this is the stricter of the two limitations). | |||
| [[Category:Xen]] | |||
| [[Category:Xen 4.2]] | |||
| [[Category:Users]] | |||
Latest revision as of 14:19, 16 August 2012
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