[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH 2/2] expert_mode: Add a new configuration option for expert users.



On 17/07/13 12:12, Ian Campbell wrote:
On Wed, 2013-07-17 at 12:03 +0100, George Dunlap wrote:
On 17/07/13 11:56, Ian Jackson wrote:
Ian Campbell writes ("Re: [Xen-devel] [PATCH 2/2] expert_mode: Add a new 
configuration option for expert users."):
On Fri, 2013-07-12 at 14:08 -0400, Konrad Rzeszutek Wilk wrote:
This could also be called 'seatbelt' option.

libxl has a variety of checks where it will fail out an operation
unless the user has provided an --force (or --ignore) parameter.
Currently one such check is for the 'vcpu-set' command which
will error out if the count of virtual cpus is greater than the
physical cpus. This parameter will ignore such checks and allow
the user to do the operations without the need for override flags.
Does this overlap  somewhat with various commands which individually
take a -f(orce) option?
Clearly it should disable all of those -f's too.

+=item B<expert_mode=BOOLEAN>
+
+Do not act on host performed checks that might lead to performance
+degradations. Currently checks are made for following operations:
+ - C<vcpu-set> - if the number of VCPUs set for a guest is higher than the
+   physical count the operation will error out.
I don't think this is a very coherent specification.  Surely it should
override "all -f options" or something similar.
I think that makes sense for some but not all.  For example, for "xl
shutdown", -f means "send an ACPI event if no PV drivers are detected".
I don't think we'd want to change that behavior with such a switch.
(Arguably -f was the wrong option to use for that in the first place,
but it's a bit late for that now.)
That's -F (for fallback not force), deliberately avoiding -f for the
reasons you might think.

If "xl shutdown -f" were to do anything it would probably be to act as
"xl destroy" (nb I don't think we should actually do that...)

Ah, right.  That makes sense.

 -G

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.