zfs code - Dec 2007 - Nvpair for storing EAs in dnode

Hi,
	In order to use DMU as backend for lustre we need to store lustre
specific information in dnodes.
	Initially we had planned to use to ZAP object for the same but
libnvpair seems to be more appropriate option. What we plan to do is use
the space available after the bonus buffer (we even plan to enlarge the
dnode to increase this space) for storing EAs.
	Fast lookup of these extended attributes in the dnode is one of the
primary requirements as lustre EAs also contains striping information.
Typical size of these EAs is about 80-128 bytes and sometimes might even
increase to 2-4KB. 
	Please let us know your ideas about such use of nvpair for EAs
considering our speed and size requirements ?

Thanks & Regards,
Girish

On Dec 13, 2007, at 10:10 PM, Girish Shilamkar wrote:
> Hi,
> 	In order to use DMU as backend for lustre we need to store lustre
> specific information in dnodes.
> 	Initially we had planned to use to ZAP object for the same but
> libnvpair seems to be more appropriate option. What we plan to do  
> is use
> the space available after the bonus buffer (we even plan to enlarge  
> the
> dnode to increase this space) for storing EAs.
> 	Fast lookup of these extended attributes in the dnode is one of the
> primary requirements as lustre EAs also contains striping information.
> Typical size of these EAs is about 80-128 bytes and sometimes might  
> even
> increase to 2-4KB.
> 	Please let us know your ideas about such use of nvpair for EAs
> considering our speed and size requirements ?
 From a use case standpoint, this would be helpful for our pNFS plans
as well.  As you can imagine, we have similar needs for EA usage and  
would
support this type of change if it meets the requirements for access  
(size
and performance).

Spencer