Re: [Qemu-devel] [RFC] qed: Add QEMU Enhanced Disk format

[Alexander Graf]

On 08.09.2010, at 10:23, Avi Kivity wrote:

> On 09/08/2010 01:27 AM, Anthony Liguori wrote:
>>> FWIW, L2s are 256K at the moment and with a two level table, it can support 
>>> 5PB of data.
>> 
>> 
>> I clearly suck at basic math today.  The image supports 64TB today.  
>> Dropping to 128K tables would reduce it to 16TB and 64k tables would be 4TB.
> 
> Maybe we should do three levels then.  Some users are bound to complain about 
> 64TB.

Why 3 levels? Can't the L2 size be dynamic? Then big images get a big L2 map 
while small images get a smaller one.


Alex