Is there any way to activate data integrity via GUI in 6.3 ?
Its only via cli. It is also limited to only verifying file level buckets.
ie. it will only show if there has been no bucket tampering and nothing else (its not event level hashing so won't show if someone used the can_delete capability).
In the .conf 2015 technical session on this feature it was indicated that this is just the start of a frame work for allowing some higher data verification features (ie. event verification) to be added later. This is just the first step in adding these.