2010-01-26 12:13 PM
Yes you can. sis runs as a background (schedue-able) service on the filer and ESX is not aware of the process. System manager gives you a good view of storage utilization before and after (I like charts).
2010-01-26 02:24 PM
Be wary though SIS is fairly resource-intensive, especially during the first run, when fingerprints of all 4k blocks get created.
So although ESX server won't be aware of what's exactly going on, your performance during de-dupe scan may suck
I'd schedule it for out of normal business hours (assuming you don't operate 24/7).