> -----Original Message----- > From: Bjoern Teipel [mailto:bjoern.tei...@internetbrands.com] > Sent: 19 March 2013 3:50 AM > To: cloudstack-users@incubator.apache.org > Subject: Re: diskless boot > > On 3/18/2013 8:43 AM, Donal Lafferty wrote: > > AFAIK, data disks are by default created in Primary Storage and not on > > the hypervisor itself. I take it you want the replacement server for > > a VM to sit in a different cluster that does not have access to the > > same primary storage > > > > Did you mean to ask whether the data disk is a 'dyanmic' hard drive image? > > 'Dynamic' disks are about as large as the actual data stored on it. They > > do not > > reserve spaced in the store for portions of the disk that have no data. In > > this > > case, I do not know the answer, as I've not much experience with KVM. > No I was more talking about the thin provisioning at LVM because I was > considering to boot those disk less VMs with the 1GB data disk on hyper visor > with local storage not to waste precious NAS. > That's why I was thinking of thin provisioning of LVM [Donal Lafferty] Whether or not to use local storage is a separate issue from whether or not to use dynamic disks. There is an option for creating local storage data disks when you create a new disk offering. I would guess that this is a 'dynamic' hard drive image, and not a 'thin provisioned' image.
> > > > IIRC, 'thin' as in 'thin provisioning' relates to templates. To reduce the > > foot > > print of the root device, a read/write 'diff' disk is created and linked to > > a read > > only 'base' disk. The 'base' disk is a copy of the template image. The > > diff > > captures changes, and grows over time as the VM updates. Because a > > number of VMs use the same 'base' image, template transfer time and the > > foot print of the root device is substantially reduced. > That's the reason why we have patchdisk files ? [Donal Lafferty] Patchdisk on KVM pass VM-specific data, whereas 'thin provisioning' is about reusing the same base image across several VMs. >From http://markmail.org/message/anaolzxlcpgrlnh5 "For those who don't know (this probably doesn't matter, but...), when KVM brings up a system VM, it creates a 'patchdisk' on primary storage. This patchdisk is used to pass along 1) the authorized_keys file and 2) a 'cmdline' file that describes to the systemvm startup services all of the various properties of the system vm." > > > > > > -----Original Message----- > > From: Teipel, Bjoern [mailto:bjoern.tei...@internetbrands.com] > > Sent: 18 March 2013 3:24 PM > > To: cloudstack-users@incubator.apache.org > > Cc: cloudstack-users@incubator.apache.org > > Subject: Re: diskless boot > > > > Hi Donal, > > > > I didn't try thin provisioning on a local LVM disk but I would expect that > > is > takes only few MB. Does CS support thin on local storage (LVM)? > > > > I can see where you question is going but a data disk,even empty would > create a dependency to the hypervisor. > > The idea for using disk less boot is not to create any dependency on > storage and only rely on memory/CPU. If the hypervisor goes down I just > start the VM in a new one. > > A data disk would be here blocking and you have to remove the data disk > from the VM before you can do any action on the VM. Doubt that would > work in CS. > > > > Bjoern > > > > On Mar 18, 2013, at 4:00 AM, "Donal Lafferty" <donal.laffe...@citrix.com> > wrote: > > > >> Let me rephrase that, > >> > >> Hi Bjoern, > >> > >> On the KVM deployment you are using, I take it that the 1 gig disk is a > >> data > disk. It the problem that its unwieldy to manage or that 1 gig takes up too > much room? > >> > >> Does the 1 gig data disk take up a lot of space on the primary storage? > >> > >> DL > >> > >> > >>> -----Original Message----- > >>> From: Mathias Mullins [mailto:mathias.mull...@citrix.com] > >>> Sent: 18 March 2013 10:53 AM > >>> To: cloudstack-users@incubator.apache.org > >>> Subject: Re: diskless boot > >>> > >>> Thin or thick provisioned? On what type of file system? > >>> > >>> Thank you, > >>> Matt > >>> > >>> On Mar 18, 2013, at 9:47 PM, "Donal Lafferty" > >>> <donal.laffe...@citrix.com> > >>> wrote: > >>> > >>>> Out of interest, how much space does an unused 1 Gig disk take up > >>>> on a > >>> hypervisor? > >>>> DL > >>>> > >>>>> -----Original Message----- > >>>>> From: Bjoern Teipel [mailto:bjoern.tei...@internetbrands.com] > >>>>> Sent: 16 March 2013 6:12 AM > >>>>> To: cloudstack-users@incubator.apache.org > >>>>> Subject: diskless boot > >>>>> > >>>>> Hi guys, > >>>>> > >>>>> one of my questions is still open: > >>>>> > >>>>> - CS doesn't support booting over ISO only without attaching a disk. > >>>>> Background is, we migrate our datacenter to boot from ISO/PXE and > >>>>> thats a big no go for me if I'm enforced to assign a 1G disk. > >>>>> Also set the minimum disk size to 0G in the global settings but > >>>>> I can't create "No Disk" Disk offerings ... > >>>>> > >>>>> Nobody had the desire to boot disk less other than me ? > >>>>> Can't believe that ;-) > >>>>> > >>>>> Thanks, > >>>>> Bjoern
