## Scheduled Downtime

Introduction

Starting with release 0.0.7, NetSaint allows you to schedule periods of planned downtime for hosts and service that you're monitoring. This is useful in the event that you actually know you're going to be taking a server down for an upgrade, etc. When a host a service is in a period of scheduled downtime, notifications for that host or service will be supressed.

Scheduling Downtime

You can schedule downtime for hosts and service through the extinfo CGI (either when viewing host or service information). Click in the "Schedule downtime for this host/service" link to actually schedule the downtime. Note: Scheduled downtime information is not preserved across program restarts, so don't schedule downtime too far in advance unless you know you aren't going to shut down or restart NetSaint before that time arrives.

Once you schedule downtime for a host or service, NetSaint will add a comment to that host/service indicating that it is scheduled for downtime during the period of time you indicated. When that period of downtime passes, NetSaint will automatically delete the comment that it added. Nice, huh?

How Scheduled Downtime Affects Notifications

When a host or service is in a period of scheduled downtime, NetSaint will not allow notifications to be sent out for the host or service. Supression of notifications is accomplished by adding an additional filter to the notification logic. You will not see an icon in the CGIs indicating that notifications for that host/service are disabled. When the scheduled downtime has passed, NetSaint will allow notifications to be sent out for the host or service as it normally would.

Overlapping Scheduled Downtime

I like to refer to this as the "Oh crap, its not working" syndrome. You know what I'm talking about. You take a server down to perform a "routine" hardware upgrade, only to later realize that the OS drivers aren't working, the RAID array blew up, or the drive imaging failed and left your original disks useless to the world. Moral of the story is that any routine work on a server is quite likely to take three or four times as long as you had originally planned...

Let's take the following scenario:

1. You schedule downtime for host A from 7:30pm-9:30pm on a Monday
2. You bring the server down about 7:45pm Monday evening to start a hard drive upgrade
3. After wasting an hour and a half battling with SCSI errors and driver incompatabilities, you finally get the machine to boot up
4. At 9:15 you realize that one of your partitions is either hosed or doesn't seem to exist anywhere on the drive
5. Knowing you're in for a long night, you go back and schedule additional downtime for host A from 9:20pm Monday evening to 1:30am Tuesday Morning.

If you schedule overlapping periods of downtime for a host or service (in this case the periods were 7:40pm-9:30pm and 9:20pm-1:30am), NetSaint will wait until the last period of scheduled downtime is over before it allows notifications to be sent out for that host or service. In this example notifications would be supressed for host A until 1:30am Tuesday morning.