Re: [Xen-API] [Squeezd] Disabling some balancing features

[Dave Scott <Dave.Scott@xxxxxxxxxxxxx>]

> > In case it's useful: the most recent versions of xapi (found in
> XenServer 6.1 and should be in XCP 1.6) can run without squeezed.
> 
> If squeezed is stopped such functions like migration (and maybe
> others) can be broken, don't they?

The operations will work as long as there is already enough memory. You're 
right though, if there isn't enough memory, then stopping squeezed isn't a 
great idea :-)

> 
> Best wishes,
> Kakadu
> 
> On Tue, Oct 23, 2012 at 5:15 PM, Dave Scott <Dave.Scott@xxxxxxxxxxxxx>
> wrote:
> > Hi,
> >
> > Dave asked:
> >> > When you try to migrate to a host which hasn't got much free
> memory,
> >> do you intend to run the existing squeezing logic?
> >
> > Kakadu replied:
> >> Nope, it should do nothing. In future another balooning daemon will
> be
> >> running and case there is not enough ememory never gonna happen. But
> >> now I'm trying to put right variables to vm params (to emulate
> >> presence of this future daemon).
> >
> > In case it's useful: the most recent versions of xapi (found in
> XenServer 6.1 and should be in XCP 1.6) can run without squeezed. So
> you can
> >
> > service squeezed stop
> >
> > and then when you try to start a VM, there won't be any squeezing at
> all. Your new daemon could do whatever it likes to manage the VM
> balloon targets independently of xapi.
> >
> > Does that help at all?
> >
> > Cheers,
> > Dave
> >
> >> Thanks for the link. I'll try to find something useful.
> >>
> >> Best wishes,
> >> Kakadu
> >>
> >>
> >> On Fri, Oct 19, 2012 at 7:27 PM, Dave Scott
> <Dave.Scott@xxxxxxxxxxxxx>
> >> wrote:
> >> >
> >> > Hi,
> >> >
> >> > Kakadu wrote:
> >> >
> >> >> Hey.
> >> >>
> >> >> I have accepted a challenge about disabling some features of
> >> >> automatical rebalancing. For example, I want squeezed to raise an
> >> >> exception while migration in case if there is not enough free
> memory
> >> >> and some squeezing needed. So I fixed reserve-memory handler in
> my
> >> >> squeezed-like daemon [1] and implemented successful result only
> when
> >> >> we can get needed memory without squeezing [2].
> >> >>
> >> >> My big problem is testing that stuff. I have vm with these
> >> >> characteristics
> >> >> $ xe vm-param-list uuid=ec1dec56-ae4f-d854-8065-e106a1139361 |
> grep
> >> >> memory
> >> >>                  memory-actual ( RO): 250609664
> >> >>                  memory-target ( RO): 250609664
> >> >>                memory-overhead ( RO): 4194304
> >> >>              memory-static-max ( RW): 250000000
> >> >>             memory-dynamic-max ( RW): 250000000
> >> >>             memory-dynamic-min ( RW): 250000000
> >> >>              memory-static-min ( RW): 250000000
> >> >>
> >> >> and while localhost migration Squeezer says that it can't
> reserve
> >> >> memory without squeezing.
> >> >>
> >> >> [20121019T14:36:28.830Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenstore-rpc] using new version of reserve_memory
> >> >> [20121019T14:36:28.830Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] force_change_host_free_memory required_mem =
> 265644
> >> >> KiB
> >> >> [20121019T14:36:28.831Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] Total non-domain reservations = 811008
> >> >> [20121019T14:36:28.831Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] domid 3 has been declared inactive
> >> >> [20121019T14:36:28.831Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] total_range = 0 gamma = 1.000000 gamma' = inf
> >> >> [20121019T14:36:28.831Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] Total additional memory over dynamic_min =
> 2675808
> >> >> KiB; will set gamma = 1.00 (leaving unallocated 0 KiB)
> >> >> [20121019T14:36:28.831Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] Maximum possible free memory if all active
> domains
> >> >> balloon down to dynamic_min = 2941452
> >> >> [20121019T14:36:28.831Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] current host free mem = 2941452 KiB (aiming for
> >> 265644
> >> >> KiB); OK; all domain targets not reached; allocation phase
> >> >> [20121019T14:36:28.831Z|debug|xenhost-1|0|reserve_memory(xapi,
> >> >> 256428)|xenops] Can't free 265644 KiB: some domains need
> squeezing
> >> >>
> >> >> I'm a little bit confused why first number is less than second in
> `
> >> >> mem = 2941452 KiB (aiming for 265644 KiB)`. Maybe I dont
> understand
> >> >> something good enough
> >> >
> >> > I think what it's trying to say is:
> >> >
> >> > The host has 2.9 GiB free but we'd like to give most of this free
> >> memory away to domains (by 'balancing'), to leave only 265644 KiB
> left.
> >> >
> >> >> So I have two questions:
> >> >> 1) How to setup parameters for testing migration with my new
> daemon?
> >> >> 2) What else pifalls I will have in my way while disabling
> >> >> autobalancing?
> >> >
> >> > When you try to migrate to a host which hasn't got much free
> memory,
> >> do you intend to run the existing squeezing logic?
> >> >
> >> > BTW there is some internal squeezed design documentation here,
> just
> >> in case its useful:
> >> >
> >> > https://github.com/xen-org/xen-api/tree/master/docs/squeezed
> >> >
> >> > Cheers,
> >> > Dave
> >> >
> >> >>
> >> >>
> >> >> Cheers,
> >> >> Kakadu
> >> >>
> >> >> [1] https://github.com/Kakadu/xcp-
> >> xapi/blob/master/debian/patches/0101-
> >> >> serred.patch#L123
> >> >> [2] https://github.com/Kakadu/xcp-
> >> xapi/blob/master/debian/patches/0101-
> >> >> serred.patch#L617
> >> >>
> >> >> _______________________________________________
> >> >> Xen-api mailing list
> >> >> Xen-api@xxxxxxxxxxxxx
> >> >> http://lists.xen.org/cgi-bin/mailman/listinfo/xen-api

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