Re: [Xen-API] xapi VDI.getPhysicalUtilisation not equals .vhd file size on disk in NFS

[Denis Cardon <denis.cardon@xxxxxxxxxxxxxxxxxxxxxx>]

Hi NDKK,

> I have a problem,
> We use XCP 1.1 and add a NFS volume on it. This NFS volume from a NFS
> Server which install on CentOS 5.6.
> When we provided many VMs in this SR, we find that the sum of  all VDIs
> Physical Utilisation (get from xapi) in this SR greater than the
> SR's Physical Utilisation .
>
> Then, I ssh to the NFS server check the VHD files size
> I use command: ls -lh  VHD_FILE_NAME
> It show that
> /-rw-r--r-- 1 root root *4.9G * Aug  8 02:38
> e77405a8-cb42-449c-b20e-912fe2a46ac2.vhd/
>
> use command: du -sh VHD_FILE_NAME
> It show that
> /*3.0G*  e77405a8-cb42-449c-b20e-912fe2a46ac2.vhd/
> /
> /
> Why they are different?
I think it has something to do with sparse file 
(http://en.wikipedia.org/wiki/Sparse_file). The "du" command might not 
be sparse file aware.
> The sum of all VDIs physical utilisation get from Xapi
> "VDI.getPhysicalUtilisation" is**like the sum of / ls -lh VHD_FILE_NAME/
> The SR's physical utilisation get from Xapi "SR.getPhysicalUtilisation"
> is like the sum of / du -sh VHD_FILE_NAME/
I don't really know which one should be displayed... Up to now we were 
only using lvm based vhd in here. Using sparse file one can overcommit 
physical disk space I guess. I don't know what happenned when a SR is 
really full and a VDI asks for an extra block.
Cheers,

Denis

> /
> /
> Is it a XAPI's BUG?
>
>
>
>
>
> This body part will be downloaded on demand.

--
Denis Cardon
Tranquil IT Systems
44 bvd des pas enchantés
44230 Saint Sébastien sur Loire
tel : +33 (0) 2.40.97.57.57
http://www.tranquil-it-systems.fr


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