Difference between revisions of "Xen 4.2 Limits"
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+ | #REDIRECT [[Xen_Release_Features]] |
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− | {{TODO|This is a work in progress. Feel free to add requests for more to the talk page or add additional information here}} |
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− | This document contains information about limits of Xen 4.2. |
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− | == CPUs & Memory == |
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− | * Xen can scale up to 4,095 host CPUs with 5Tb of RAM. |
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− | * Using Para Virtualization (PV), Xen supports a maximum of 512 VCPUs with 512Gb RAM per guest. |
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− | * Using Hardware Virtualization (HVM), Xen supports a maximum of 128 VCPUs with 512Gb RAM per guest. |
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− | {{TODO|Should this be 256 for HVM? }} |
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− | Note that in theory Xen supports 8192 VCPUs with PV, but event channel limitations (4k per guest) make it impossible for a guest this huge to |
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− | 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. |
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− | == Other Limits == |
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− | * Maximum of 32K interrupts and 2k PCI segments: this limits the number of devices that can be used in two ways: |
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− | ** 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]) |
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− | ** 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). |
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− | [[Category:Xen]] |
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− | [[Category:Xen 4.2]] |
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− | [[Category:Users]] |
Latest revision as of 14:19, 16 August 2012
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