There are plenty of services out there that let you monitor your infrastructure and servers performance and uptime. In fact, you would be foolish not to have at least a couple monitoring your site’s URL so that you can be notified when issues do occur. However, there are fewer services that actually let you monitor AND troubleshoot at a much more granular level. Over the past few weeks, I have been testing out once such service called Server Density.
Whether you have 1 server or multiple, Server Density has your monitoring covered with both free and paid for pricing plans (details here). The folks over at Boxed Ice, the makers of Server Density set me up with the premium version of their service so that I could test it out on my personal blog which is running on GoGrid. Before I go into my analysis of the service, here are some of the highlights (pretty much all of which I have tested):
- Monitoring of Core Measurables:
- CPU Load (included w/ free acct)
- Memory (included w/ free acct)
- Processes (included w/ free acct)
- Disk Usage
- Network Traffic
- iPhone Push Notifications
- Graphing – all configured monitors have graphs associated with them to help you visualize server performance
- Snapshots in Time – allows you to click a point on a graph to know exactly what was happing when your servers were acting up.
Currently, Server Density works with Linux servers but I’m told that Windows support will be coming. Be sure to read their FAQ.
Installing Server Density
Primarily, all that you need to install Server Density is access to your Linux distro (you don’t even need root access to install the agent). You simply install the monitoring agent and away you go. There is a great video that shows how to install on GoGrid specifically, using our API key/functionality to pull in all available servers (more details about Cloud support can be found in this blog post):
Installing the basic monitoring agent is very straightforward. The process is clearly documented within the Server Density Documentation section of their site. The only issues that I had was in setting up some of the more advanced monitors as I had to direct the traffic through a particular port (specific to the Apache monitoring). My issues had nothing to do with the install, but rather with the configuration of my server so that I could run the Apache monitoring through a particular port. The Server Density team provides great support in assisting you with configuration issues.
Using Server Density
Once you get Server Density installed and configured on your servers, the Agent will begin pushing out data about your server. There are a few ways that you can view your data: online and via an iPhone app (requires the paid version of the service).
Online Viewing & Management
When you log into your Service Density account, the first thing that you see is your dashboard which will list out any and all servers currently running (automatically refreshes every 60 seconds):
Also listed within the dashboard are the last 5 triggered events based on the alert thresholds you configure (you can see below that while I passed the threshold on “load average”, it wasn’t sustained long enough to have an alert sent – except for one case):
If you want to see each of the monitors in a graph form, simply click on the server and you will be presented with a variety of options, including but not limited to:
Load Average (when you mouse over a particular peak, you can see the values as well as drill down on that particular event):
Physical Memory (shows cached, free and used memory):
There are other graphs including: Processes, Swap Usage, Disk, Network Traffic, Apache Status, Nginx Status and MySQL Status (all depending on your configuration).
But the real power of the reporting comes when you want to troubleshoot a particular point in time. Simply click on a point on the graph, and you are given details around that particular snapshot:
Snapshot Overview (all of the stats right at that point in time):
Disk Usage, MySQL status and Network Traffic
The Top 4 CPU and Memory Processes at that point in time (mouse over shows details):
And a List of Processes running at that point in time:
Once you set up your monitoring, you can add a variety of Alerts that can be sent via SMS, Email or via iPhone Push Notification:
It’s easy to pause notification as well as set a “wait time” before a notification is sent. This is useful in preventing too many false positives from being sent. You can also configure an “All Clear” email to be sent. Similarly, you can set Alerts to only be delivered one time or on a pre-defined basis.
Server Density iPhone Application
Those customers who choose to pay for the monitoring also get access to a nifty iPhone app that pulls the data in real-time. Shaking your iPhone refreshes the data and there are a few fields that can be tapped to include additional measures (e.g., Disk Usage, Apache Status and Network Traffic):
All of the stats that are included in the web-dashboard are also included in the iPhone. If you rotate your iPhone, you can see detailed charts on a variety of metrics.
Alerts can be Paused and Started from the Alert tab and you can see the Last 5 Alerts that were triggered.
Do note that Server Density does say that you probably should NOT rely on iPhone Push Notification for critical Alerts because if you are in an area of no cell phone coverage and there are a series of alerts, it will only pull the latest alert.
Whether you use Server Density or another monitoring service to keep track of your server environments, the fact that you ARE monitoring is an important step!
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