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From Hari Kannan <hari.kan...@citrix.com>
Subject RE: [PROPOSAL] Raise cluster size limit to 16 on VMware
Date Thu, 10 Jan 2013 07:12:36 GMT
Hi Koushik,

I have a question/concern -

The "limitations" are multi-dimensional - for example, vSphere 5.0 clusters hosting linked
clone pools are limited to 8 ESXi hosts when using VMFS datastores and 32 ESXi hosts when
using only NFS datastores. In 5.1, they made both 32 hosts. I think 4.0 had a different set
of values. 

In other words, the host limits are hypervisor type, hypervisor version, storage technology
etc. i.e. we cant set the hard limit as 32 as 5.0 did not support it for VMFS..

Hari

-----Original Message-----
From: Koushik Das [mailto:koushik.das@citrix.com] 
Sent: Wednesday, January 9, 2013 10:30 PM
To: cloudstack-dev@incubator.apache.org
Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on VMware

To clarify some more.

What I have suggested is to have a max. hosts per cluster limit based on specific HV version.
For e.g. for Vmware

Version 4.0 will have a max. limit of X (i.e. in any CS Vmware 4.0 cluster, the max. number
of hosts that can be added is X) Version 4.1 will have a max. limit of Y Version 5.0 will
have a max. limit of Z

Based on the vmware specification X, Y, Z are all 32. As part of best practices (in documentation)
all the limitations discussed as to why the limit was set to 8 earlier can be mentioned. The
idea is that CS shouldn't impose any artificial restrictions and rely only on HV specifications
to the extent possible.

For any new supported version another entry can be added to the hypervisor_capabilities table.

As Alex mentioned, the admin is free to decide on the number of hosts that needs to be added
in a cluster as long as the hard max. limits are not exceeded.

-Koushik

> -----Original Message-----
> From: Koushik Das [mailto:koushik.das@citrix.com]
> Sent: Tuesday, January 08, 2013 11:45 PM
> To: cloudstack-dev@incubator.apache.org
> Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on VMware
> 
> See inline
> 
> -Koushik
> 
> > -----Original Message-----
> > From: Alex Huang [mailto:Alex.Huang@citrix.com]
> > Sent: Tuesday, January 08, 2013 11:24 PM
> > To: cloudstack-dev@incubator.apache.org
> > Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on VMware
> >
> > Koushik,
> >
> > I believe what you pointed out there is the maximum limit for the
> hypervisor.
> 
> Yes. Maximum based on the HV version.
> 
> >
> > Hari,
> >
> > What's the point of the admin setting these values?  Afterall, he's 
> > the one who's adding hosts himself?  If he wants more, why should cs 
> > stop
> him?
> >
> > --Alex
> >
> > > -----Original Message-----
> > > From: Hari Kannan [mailto:hari.kannan@citrix.com]
> > > Sent: Tuesday, January 08, 2013 9:44 AM
> > > To: cloudstack-dev@incubator.apache.org
> > > Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on VMware
> > >
> > > Hi Koushik,
> > >
> > > Can you please elaborate
> > >
> > > a) how the admin gets to set this value?
> 
> Why should the admin be allowed to change these values? These are the 
> max. limit supported by the specific HV based on the version.
> 
> > > b) is this value set on a per cluster basis? If so, what is the default value?
> 
> It's not per cluster.
> 
> > >
> > > Hari
> > >
> > > -----Original Message-----
> > > From: Koushik Das [mailto:koushik.das@citrix.com]
> > > Sent: Monday, January 7, 2013 4:57 AM
> > > To: cloudstack-dev@incubator.apache.org
> > > Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on VMware
> > >
> > > Didn't see any feedback, so am assuming that the approach seems 
> > > reasonable. I will go ahead and start with the implementation. Not 
> > > planning to write a FS as this is a small feature and the below 
> > > mail
> > summarizes it.
> > >
> > > -Koushik
> > >
> > > > -----Original Message-----
> > > > From: Koushik Das [mailto:koushik.das@citrix.com]
> > > > Sent: Thursday, January 03, 2013 5:26 PM
> > > > To: cloudstack-dev@incubator.apache.org
> > > > Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on VMware
> > > >
> > > > So based on the discussions would it be fair to conclude that 
> > > > this should be handled by adding some column like 'max_host_per_cluster'
> > > > in hypervisor_capabilities table. Currently the following 
> > > > version entries are present for Vmware. For each version an 
> > > > appropriate value can be associated based on the limitations/actual supported.
> > > > For other HVs where this setting is not applicable some dummy 
> > > > value, say (-1) can be
> > > entered.
> > > >
> > > > hv_type	hv_version
> > > > VMware	default
> > > > VMware	4.0
> > > > VMware	4.1
> > > > VMware	5.0
> > > >
> > > > Let me know if there is a consensus on this.
> > > >
> > > > Thanks,
> > > > Koushik
> > > >
> > > > > -----Original Message-----
> > > > > From: Alex Huang [mailto:Alex.Huang@citrix.com]
> > > > > Sent: Thursday, December 20, 2012 10:08 PM
> > > > > To: cloudstack-dev@incubator.apache.org
> > > > > Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on 
> > > > > VMware
> > > > >
> > > > > +1
> > > > >
> > > > > The more we move these types of things out of configuration 
> > > > > and into component specific references the better.
> > > > >
> > > > > --Alex
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Tamas Monos [mailto:tamasm@veber.co.uk]
> > > > > > Sent: Thursday, December 20, 2012 8:10 AM
> > > > > > To: cloudstack-dev@incubator.apache.org
> > > > > > Subject: RE: [PROPOSAL] Raise cluster size limit to 16 on 
> > > > > > VMware
> > > > > >
> > > > > > Hi,
> > > > > >
> > > > > > I'd recommend removing any hard limits from CS and introduce

> > > > > > a variable like "max.guest.limit" on the Hypervisor Capabilities
page.
> > > > > > This value could default to 8, but should the admin decide 
> > > > > > otherwise could be set to anything.
> > > > > >
> > > > > > Regards
> > > > > >
> > > > > > Tamas Monos                                               DDI
        +44(0)2034687012
> > > > > > Chief Technical                                            
Office    +44(0)2034687000
> > > > > > Veber: The Hosting Specialists               Fax         +44(0)871
522 7057
> > > > > > http://www.veber.co.uk
> > > > > >
> > > > > > Follow us on Twitter: www.twitter.com/veberhost Follow us on
> > > > Facebook:
> > > > > > www.facebook.com/veberhost
> > > > > >
> > > > > > -----Original Message-----
> > > > > > From: David Nalley [mailto:david@gnsa.us]
> > > > > > Sent: 20 December 2012 15:25
> > > > > > To: cloudstack-dev@incubator.apache.org
> > > > > > Subject: Re: [PROPOSAL] Raise cluster size limit to 16 on 
> > > > > > VMware
> > > > > >
> > > > > > On Thu, Dec 20, 2012 at 1:54 AM, Koushik Das 
> > > > > > <koushik.das@citrix.com>
> > > > > > wrote:
> > > > > > > This http://www.vmware.com/pdf/vsphere5/r51/vsphere-51-
> > > > > > configuration-maximums.pdf mentions that the max. can be 32

> > > > > > for ESX
> > > > 5.1.
> > > > > > Any specific reason to make it 16? Also it needs to be seen

> > > > > > that this limit works across all supported ESX versions.
> > > > > > >
> > > > > > > -Koushik
> > > > > > >
> > > > > >
> > > > > > Yes - the different versions having different limits 
> > > > > > complicates things a
> > > > bit.
> > > > > > 5.1 = 32, 5.0 = 16 4.x = 8?
> > > > > >
> > > > > > --David
> > > > > >


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