I gues the volume got formatted at windows end so that is why it showing me 65gb used. Please correct me if wrong .
I have set volume option Fractional Reserve to 0 and have the snapshot enabled . Also the volume is getting snapmirror to DR filer.
1) When user deletes the few gb's of data and add fresh data the all deleted data goes into snapshot and volume gets full and it takes lun offline.
Wed Apr 24 11:33:03 IST [filer0011: scsitarget.lun.noSpace:error]: LUN '/vol/exch_index_1/exch_index_1' has run out of space. Wed Apr 24 11:33:03 IST [filer0011: lun.offline:warning]: LUN /vol/exch_index_1/exch_index_1 has been taken offline
2) To avoid this I have disabled the snapshot generation and break the snapmirror relation ship with DR volume . Now again when use starts dumping the fresh data it started eating up the snapshot space (snapmirror snapshot started growing ) and once vailable space in volume is eaten up by snapshot the volume gets full and LUN goes offline again.
Below is volume status when only snapmirror snapshot was there and user was dumping fresh data.
The first bit of 'help' I might be able to offer, is that I don't think you've posted this question in the right community space. I'm not certain which community space would be better for SAN questions related to Fractional Reserves and Thin Provisioning for SAN... but a quick search might make this a better place for your discussion (https://communities.netapp.com/community/products_and_solutions).
That said, I may have some small advice for you:
You mentioned setting your fractional reserve to 0. That's good, but you should also ensure that your volume garantees are set to 'none'. I experienced issues in the past when I only tried to set the fractional reserve to 0, but not the volume guarantees.
A reason your LUN is taking up the full 65GB in your volume might be due to the space reservations on the LUN. If your space resevations on the LUN are enabled, the size of the LUN (65GB in this case), is provisioned right up front out of the volume. If you would like the LUN to 'grow-as-you-go', then it would be better to disable the space reservations for the LUN
Another reason your LUN might be set to 65GB is if the application (like Oracle) is using the LUN, then it will 'touch' each block in the LUN.
Consuming snap space. The data is going into / out of your LUN. What is happening with the snapshot (after a snapshot is taken), is it is keeping track of all of the changes to the LUN. This is either data that is written OR deleted. This is why it's possible to 'snap restore' to a prior state and either recover data mistakenly removed, or reset any unwanted changes.
If you don't want your LUN to go offline, you may also want to look into the auto-grow and auto-delete options.
Again, I hope this helps. If not, you might try posting your question in the other forum so a wider audience can provide advice.