Volume usable size and lun

[deygaurab]

Hi,

I have trying to understand the space usage a volume displays when a lun is created in it. For example,

volume size =625g (guarantee=none)

lun size=500g (space reservatio=disabled)

FR=20%

There is a snapshot(snapmirror) in te volume

The lun show -v command reports the lun consumtion as 363g

The df -g output of the volume reports 27gb usaed and 597gb free. whereas the host sees 90% utilised for the same lun mounted as a datastore? I am having a hard time understanding this equation. If the volume usage reported more than the what is reported in the host side than I would have understood that that there was sme changes in the data and space reclamation needed to be run. But I am not able to understand why would a volume report only 27g of usage and 597g of availble space.

Any suggestions would be greatly appreciated.

Cheers

Rahul

[columbus_admin]

Sorry Rahul,

     I am just finishing up 48 hours of watching my one of my 3020s panic and reboot.  Scott is correct, the snapshot is de-dupe aware and if the block was de-duped before, the snapshot only creates another pointer data for the snapshot.

As for fractional reserve for the LUN, I have to defer to Scott, as we don't use them, so my experience is very limited.  Keep in mind that reserve used is the important number, even though it is reserved, usage would still only show what is actually in the reserve at that time, so if you didn't have a full 72G of snaps from the LUN in the reserve, it would only report actual used space.

- Scott

[deygaurab]

Thanks a lot to both of you