Linux – How to monitor log files via Nagios

As you stated, because Exchange uses the store.exe process for all mailbox databases, it is not possible to monitor individual mailbox database that way. There may be ways to do so by talking directley to Exchange, but I don't know of any process for Nagios that can do that.

The store.exe process is the Exchange Information Store service, this can be monitored by Nagios. If the mailbox databases dismounts because of diskspace issues, and many other issues it is likely this server will have stopped as well. Monitoring this should give you a good indication of mailbox issues

This article is an excellent tutorial on setting up monitoring for Exchange services and includes a lot of info on the different things you can check to monitor your Exchange servers health.

[Edit]

Windows Performance Counters does have a counter for the Exchange store, the MSExchangeIS Mailbox, counter so this may also be able to be used.

You can get a pretty good measure of this using the iostat tool.

% iostat -dx /dev/sda 5

Device:         rrqm/s   wrqm/s     r/s     w/s   rsec/s   wsec/s avgrq-sz avgqu-sz   await  svctm  %util
sda               0.78    11.03    1.19    2.82    72.98   111.07    45.80     0.13   32.78   1.60   0.64

The disk utilisation is listed in the last column. This is defined as

Percentage of CPU time during which I/O requests were issued to the device (band-width utilization for the device). Device saturation occurs when this value is close to 100%.