Ubuntu – spares missing on ubuntu mdadm software raid 5 how to disable

I want to understand and if it makes sense, disable the alert message I receive about spares missing on my ubuntu linux software raid 5.

I used mdadm and set up a /dev/md0 raid volume made up of 3 hard drives.

I then set up email alerts so I can see when there is a problem with it.

I often get these 'spare missing' alerts, and I assume that means there is a second spare defined and I do not have one.

I am looking to clarify that this is actually not really a problem, and that I can change a setting to tell mdadm I do not have a second spare (I have only 3 drives). My system should continue running if 1 drive goes down?

Here is the alert message:

This is an automatically generated mail message from mdadm running on myserver

A SparesMissing event had been detected on md device /dev/md0.

Faithfully yours, etc.

P.S. The /proc/mdstat file currently contains the following:

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sdc1[1] sdb1[0] sdd1[2]
      1953519488 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

unused devices: <none>