Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-19 Thread Stefan Hajnoczi
On Tue, Oct 30, 2012 at 08:59:32PM -0600, Charles Arnold wrote: > The VHD specification allows for up to a 2 TB disk size. The current > implementation in qemu emulates EIDE and ATA-2 hardware which only allows > for up to 127 GB. This disk size limitation can be overridden by allowing > up to 255

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-15 Thread Thanos Makatos
I'm not sure I understand your question. In XenServer blktap2 we set CHS to 65535*16*255 in the VHD metadata for disks larger than 127GB. We don't really care about these values, we just store them in the VHD metadata. > -Original Message- > From: Paolo Bonzini [mailto:pbonz...@redhat.co

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-15 Thread Paolo Bonzini
Il 15/11/2012 17:46, Charles Arnold ha scritto: >>> We don't use qemu's VHD driver in XenServer. Instead, we use blktap2 >>> >> to create a block device in dom0 serving the VHD file in question, >>> >> and have qemu open that block device instead of the VHD file itself. >> > >> > Yes, the question

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-15 Thread Charles Arnold
>>> On 11/14/2012 at 09:35 AM, in message <50a3c853.4010...@redhat.com>, Paolo Bonzini wrote: > Il 14/11/2012 17:25, Thanos Makatos ha scritto: >> We don't use qemu's VHD driver in XenServer. Instead, we use blktap2 >> to create a block device in dom0 serving the VHD file in question, >> and have

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-14 Thread Thanos Makatos
We don't use qemu's VHD driver in XenServer. Instead, we use blktap2 to create a block device in dom0 serving the VHD file in question, and have qemu open that block device instead of the VHD file itself. > -Original Message- > From: Stefano Stabellini [mailto:stefano.stabell...@eu.citri

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-14 Thread Paolo Bonzini
Il 14/11/2012 17:25, Thanos Makatos ha scritto: > We don't use qemu's VHD driver in XenServer. Instead, we use blktap2 > to create a block device in dom0 serving the VHD file in question, > and have qemu open that block device instead of the VHD file itself. Yes, the question is how you handle dis

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-13 Thread Stefano Stabellini
On Tue, 13 Nov 2012, Paolo Bonzini wrote: > Il 12/11/2012 20:12, Charles Arnold ha scritto: > > Ping? > > > > Any thoughts on whether this is acceptable? > > I would like to know what is done by other platforms. Stefano, any idea > about XenServer? > I am not sure, but maybe Thanos, that is wo

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-13 Thread Paolo Bonzini
Il 12/11/2012 20:12, Charles Arnold ha scritto: > Ping? > > Any thoughts on whether this is acceptable? I would like to know what is done by other platforms. Stefano, any idea about XenServer? Paolo > - Charles > On 10/30/2012 at 08:59 PM, in message <50a0e561.5b74.009...@suse.com>, >>>

Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-11-12 Thread Charles Arnold
Ping? Any thoughts on whether this is acceptable? - Charles >>> On 10/30/2012 at 08:59 PM, in message <50a0e561.5b74.009...@suse.com>, >>> Charles Arnold wrote: > The VHD specification allows for up to a 2 TB disk size. The current > implementation in qemu emulates EIDE and ATA-2 hardware whic

[Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

2012-10-30 Thread Charles Arnold
The VHD specification allows for up to a 2 TB disk size. The current implementation in qemu emulates EIDE and ATA-2 hardware which only allows for up to 127 GB. This disk size limitation can be overridden by allowing up to 255 heads instead of the normal 4 bit limitation of 16. Doing so allows di