Engine Yard Developer Center

About Alerts for Your Environment

Alert Types

Load Average

Load average represents the average system load an instance experiences over a period of time.

Current Thresholds:

  • Warn: 4 x vCPU
  • Fail: 10 x vCPU

For example: a 1 vCPU, the load would be 4.00 but a 5 vCPU, it would be 20.00.

Note: A vCPU is the same as an ECU (an Amazon EC2 Compute Unit).

For general information about how load average is calculated, see Load (computing).

IO-Wait

The instances cpu is waiting for disk writes to complete before it can move on to other operations.

Current Thresholds:

  • Warn: 40% iowait
  • Fail: 80% iowait 

Swap Used

The amount of swap hard disk space used as virtual memory resources. High swap is an indication that an instance needs more memory.

Current Thresholds:

  • Warn: 128 MB Swap Used
  • Fail: 384 MB Swap Used 

Free Space

Free space is monitored on these mount points: /, /data, /db, and /mnt.

You might not realize the instance is almost out of disk space until you get this alert. The thresholds are calculated based on the space allocated to the mount point.

Current Thresholds:

  • Warn: If the disk space for a particular mount point is 10 GB or less, then the warning threshold is 70% full. If the disk space is greater than 10 GB, then the warning threshold is 80% full.
  • Fail: 90% of disk space is full.

The best practice is to review the content of the volume and confirm the usage is appropriate to your use case. If you do need to increase the available space it might be possible for Engine Yard Support to resize your volume online if your instance is "current generation"; if not, you will need to replace the instance with one that includes a larger volume.


If you have feedback or questions about this page, add a comment below. If you need help, submit a ticket with Engine Yard Support.

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Comments

  • Avatar
    Arthur Ketcham

    We'd love to have the ability to set these. (Specifically disable swap alerts, as we are flooded with these during intentional high load processes)

  • Avatar
    Tasha Drew

    Hi Arthur, 

    Thanks for the note! I've added a feature request to track this feature. https://support.cloud.engineyard.com/entries/25252036-Ability-to-set-alert-levels-from-the-dashboard << You can subscribe to it to track when we implement it. 

    For now, if you open a support ticket, they can set levels for you to receive alerts manually. Of course, this isn't optimal if you're looking to just disable them for a few hours, but they can do that too. 

    Cheers, Tasha 

  • Avatar
    Ryan Porter

    I just happened to see this while looking for ways to get deployment notifications into a Campfire chat room (no such luck) and I wanted to mention that you can already control those alerts by yourself without asking support, using custom Chef recipes.  We had to do it for some instances that we intentionally run at maximum load.  Here's how I do it: https://gist.github.com/endymion/7432783

     

    (Proper credit: I did not come up with this myself, Engine Yard support suggested it when I asked.)

  • Avatar
    John Yerhot

    Hi Ryan!

    Completely right, thanks for mentioning it!  The full cookbook is located at: https://github.com/engineyard/ey-cloud-recipes/tree/master/cookbooks/collectd

    John

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