Some servers were unreachable today, fortunately they were all monitored by Oracle Enterprise Manager 12c, so I see them on the summary page and contacted the related sysadmin staff to fix the problems. I’ve not set up notification mails yet (this is a new implementation), so I didn’t get emails when the servers are down. I wondered when they shutdown and check one of the servers “Availability” page (while it’s down).
If you examine the screenshot, you can see that the agent is unreachable (and also the host) since 10:39. It was 15:59 when I check the page, so it was down for 3 hours and 10 minutes. After I contacted the sysadmins, they make the server up at 16:10. I did manually start the agent after the server is up, and waited a while so the agent can upload the data to OMS, then I checked the Availability Page again. What do you expect to see?
I don’t know what you expect, but I was not expecting to see %100 availability for last 24 hours I checked another server which has down for 2-3 hours last night, and see that it’s shown %100 available! I’m already using the latest EM12c(126.96.36.199.0) now checking if there’s a fix for it.