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qm: fix typos and improve wording in CPU Types section

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Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
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Fiona Ebner 2023-06-20 09:25:25 +02:00
parent 41379e9a77
commit 57bb28ef95
1 changed files with 18 additions and 15 deletions
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@ -352,9 +352,9 @@ CPU Type
QEMU can emulate a number different of *CPU types* from 486 to the latest Xeon
processors. Each new processor generation adds new features, like hardware
assisted 3d rendering, random number generation, memory protection, etc ...
Also, a current generation can be upgraded through microcode update with bugs
or security fixes.
assisted 3d rendering, random number generation, memory protection, etc.. Also,
a current generation can be upgraded through microcode update with bug or
security fixes.
Usually you should select for your VM a processor type which closely matches the
CPU of the host system, as it means that the host CPU features (also called _CPU
@ -364,25 +364,28 @@ as your host system.
This has a downside though. If you want to do a live migration of VMs between
different hosts, your VM might end up on a new system with a different CPU type
or a different microcode.
If the CPU flags passed to the guest are missing, the qemu process will stop. To
remedy this QEMU has also its own virtual CPU types, that {pve} uses by defaults.
or a different microcode version.
If the CPU flags passed to the guest are missing, the QEMU process will stop. To
remedy this QEMU has also its own virtual CPU types, that {pve} uses by default.
Default is x86-64-v2-AES, compatible with Intel >= Westmere and Amd >= Opteron_G4
The backend default is 'kvm64' which works on essentially all x86_64 host CPUs
and the UI default when creating a new VM is 'x86-64-v2-AES', which requires a
host CPU starting from Westmere for Intel or at least a fourth generation
Opteron for AMD.
In short:
If you don’t care about live migration or have a homogeneous cluster where
all nodes have the same CPU and same microcode version, set the CPU type to host, as in
theory this will give your guests maximum performance.
If you don’t care about live migration or have a homogeneous cluster where all
nodes have the same CPU and same microcode version, set the CPU type to host, as
in theory this will give your guests maximum performance.
if you care about live migration and security, and you have only Intel CPU or only AMD CPU,
choose the lowest generation cpu model of your cluster.
If you care about live migration and security, and you have only Intel CPUs or
only AMD CPUs, choose the lowest generation CPU model of your cluster.
if you care about live migration without security, or have mixed intel/amd cluster,
choose the lowest compatible virtual qemu type.
If you care about live migration without security, or have mixed Intel/AMD
cluster, choose the lowest compatible virtual QEMU CPU type.
NOTE: Intel <> AMD migrations have no guarantee to work
NOTE: Live migrations between Intel and AMD host CPUs have no guarantee to work.
Intel CPU Types since 2007