What specific version of Pulse 6 did you upgrade it to?
On 6.1, that is more of a warning only. It does that if there is 30% remaining on the disk. The maintenance job of Pulse should still kick-in and will try to help out in the maintenance of the diskspace from within its directory. If the diskspace remaining dips even further, Elasticsearch will be on read-only mode once it hits 15%.
Thanks for bringing this up! We will have a look on this area to check further and target to address it in an upcoming release.
So, I have some concerns, is it more of the warning then will it be ok to do the upgrade in prod env.,
how can i ensure not to receive this warning,
can there be any possibility to know how much space Elasticsearch will take as per current indices?
Also, this is dev env. which is not actively used, current disk space still remains 297GB , should we raise request for more disk space, if yes, then how much?
The diskspace of the indices occupied by Elasticsearch is as can be seen from the About / Status page above. As you can see, it is at ~500MB.
As for the warning itself how not to see it, please see above post.
On the diskspace regarding dev environment, that is up to you or the client to decide on. As mentioned above, that is a warning only. Pulse itself will try to do a self-maintenance within its directory wherever possible and manage its size.