docs: clarify virsh setvcpus and setmem usage with active domains

Addresses BZ # 622534:

  https://bugzilla.redhat.com/show_bug.cgi?id=622534
This commit is contained in:
Justin Clift 2011-01-14 07:45:37 +11:00
parent 221151813c
commit efc892ad6f

View File

@ -568,12 +568,19 @@ XEN_CREDIT scheduler and are now I<DEPRECATED>.
=item B<setmem> I<domain-id> B<kilobytes>
Change the current memory allocation in the guest domain. This should take
effect immediately. The memory limit is specified in
kilobytes.
Immediately change the current memory allocation for an active guest domain.
For Xen, you can only adjust the memory of a running domain if the
domain is paravirtualized or running the PV balloon driver.
Some hypervisors require a larger granularity than kilobytes, and requests
that are not an even multiple will either be rounded down or rejected. For
example, vSphere/ESX rejects the parameter unless the kB argument is evenly
divisible by 1024 (that is, the kB argument happens to represent megabytes).
For Xen, you can only adjust the memory of a running domain if the domain is
paravirtualized or running the PV balloon driver.
Note, this command only works on active guest domains. To change the memory
allocation for an inactive guest domain, use the virsh B<edit> command to
update the XML <memory> element.
=item B<setmaxmem> I<domain-id> B<kilobytes>
@ -593,23 +600,31 @@ QEMU/KVM supports I<--hard-limit>, I<--soft-limit>, and I<--swap-hard-limit>.
=item B<setvcpus> I<domain-id> I<count> optional I<--maximum> I<--config>
I<--live>
Change the number of virtual CPUs active in the guest domain. Note that
I<count> may be limited by host, hypervisor or limit coming from the
original description of domain.
Change the number of virtual CPUs active in a guest domain. By default,
this command works on active guest domains. To change the settings for an
inactive guest domain, use the I<--config> flag.
For Xen, you can only adjust the virtual CPUs of a running domain if
the domain is paravirtualized.
The I<count> value may be limited by host, hypervisor, or a limit coming
from the original description of the guest domain. For Xen, you can only
adjust the virtual CPUs of a running domain if the domain is paravirtualized.
If I<--config> is specified, the change will only affect the next
boot of a domain. If I<--live> is specified, the domain must be
running, and the change takes place immediately. Both flags may be
specified, if supported by the hypervisor. If neither flag is given,
then I<--live> is implied and it is up to the hypervisor whether
I<--config> is also implied.
If the I<--config> flag is specified, the change is made to the stored XML
configuration for the guest domain, and will only take effect when the guest
domain is next started.
If I<--maximum> is specified, then you must use I<--config> and
avoid I<--live>; this flag controls the maximum limit of vcpus that
can be hot-plugged the next time the domain is booted.
If I<--live> is specified, the guest domain must be active, and the change
takes place immediately. Both the I<--config> and I<--live> flags may be
specified together if supported by the hypervisor.
When neither the I<--config> nor I<--live> flags are given, the I<--live>
flag is assumed and the guest domain must be active. In this situation it
is up to the hypervisor whether the I<--config> flag is also assumed, and
therefore whether the XML configuration is adjusted to make the change
persistent.
The I<--maximum> flag controls the maximum number of virtual cpus that can
be hot-plugged the next time the domain is booted. As such, it must only be
used with the I<--config> flag, and not with the I<--live> flag.
=item B<shutdown> I<domain-id>