On Tue, Dec 29, 2009 at 12:07:58PM +0200, Avi Kivity wrote:
> Guests use this number as a hint for alignment and I/O request sizes. Given
> that modern disks have 4K block sizes, and cached file-backed images also
> have 4K block sizes, this hint can improve guest performance.
>
> We probably nee
On Tue, Dec 29, 2009 at 02:39:38PM +0100, Luca Tettamanti wrote:
> Linux tools put the first partition at sector 63 (512-byte) to retain
> compatibility with Windows;
Well, some of them, and depending on the exact disks. It's all rather
complicated.
> > It has been discussed for hardware disk de
On 12/29/2009 03:39 PM, Luca Tettamanti wrote:
Ugh, I hope you're wrong ;-) AFAICS remapping will lead only to
headaches... Linux does not have any problem with aligned partitions.
And in fact, that was the motivation for this patch, as parted will
align based on the physical block size.
On Tue, Dec 29, 2009 at 2:21 PM, Jamie Lokier wrote:
> Avi Kivity wrote:
>> Guests use this number as a hint for alignment and I/O request sizes.
>
> It's not just a hint. It is also the "radius of corruption on failed
> write" - important for journalling filesystems and databases.
>
>> Given
>>
Avi Kivity wrote:
> Guests use this number as a hint for alignment and I/O request sizes.
It's not just a hint. It is also the "radius of corruption on failed
write" - important for journalling filesystems and databases.
> Given
> that modern disks have 4K block sizes,
Do they, yet?
> and cach
Guests use this number as a hint for alignment and I/O request sizes. Given
that modern disks have 4K block sizes, and cached file-backed images also
have 4K block sizes, this hint can improve guest performance.
We probably need to make this configurable depending on machine type. It
should be t
