Coradiant TrueSight

Several of us saw a demo of Coradiant Truesight yesterday (first mentioned in the BbWorld Monitoring post). Most of the demo, I spent trying to figure out the name Jeff Goldblum as one of team giving the demo had the voice and mannerisms of the actor’s characters. Had he mentioned a butterfly, then I definitely would have clapped. The other reminded me of John Hodgman.

Something I had not noticed at the time, but a reoccurring point of having Truesight is to tell our users, “Here is evidence the problem is on your end and not ours.” This assumes the users are rational or will even believe the evidence. They wish the problem never occurred (preference) and a resolution (secondarily). Preventing every problem, especially issues outside our domain, probably is outside the scope of the budget we receive. So, we are left with resolving the issues. Especially scary are the users who take evidence the problem is on their end or their ISP’s end to mean, “This is all your fault.”

Resolutions we can we offer are:

  1. Hardware change – We can replace or alter the configuration of the hardware components of the network, storage, database, or application.
  2. Software change – We can alter the configuration of the software components of the network, storage, database, or application.
  3. Request a code change from a vendor – We can work with our vendors to get a code change. These take forever to implement.
  4. Suggest a user resolve the issue
    1. We can provide a work around (grudgingly accepted, remember the preferred wish is the problem never occurred).
    2. We suggest configuration changes the user can make to resolve the problem.

Truesight provides us information to help us try to resolve issues. Describing the information provided as “facts” was a nice touch. At Valdosta State, I gave up on users reporting the browsers accurately and captured the information from the User-Agent header. Similarly, at the USG, I’ve found users disagree ~30% of the time about the version of the browser according to the User-Agent string. Heck, they have errors in the name of the class ~40% of the time. My favorite is something took 15 minutes, but all I could find was it took four minutes. Ugh. Because Truesight is capturing the header info, it ought to be much easier to confirm what users were doing and where problems occurred more accurately than the users can describe.

After receiving all the “facts”, we still have to determine the cause. Truesight helps us understand the scope of the problem by how many users, how many web servers, and how many pages are affected by slowness to what degree. As a DBA and administrator, my job identifying cause ought to be easier, though quantifying how much easier probably is difficult to say.

Part of why: (Mostly speculation.) Problems identified as a spike in anything other than “Host” are external causes. These are causes in front of the device. Causes behind the device are “Host”. If these were more narrowly broken down, the maybe we could better determine cause. That would require knowledge web browsers typically would not know like the server processing time, query processing time, or even the health of the servers.

tag: Blackboard Inc, Coradiant, , user agent,

BbWorld Presentation Redux Part II – Monitoring

Much of what I might write in these posts about Vista is knowledge accumulated from the efforts of my coworkers.

This is part two in a series of blog posts on our presentation at BbWorld ’07, on the behalf of the Georgia VIEW project, Maintaining Large Vista Installations (2MB PPT).

Part one covered automation of Blackboard Vista 3 tasks. Next, let’s look at monitoring.

Several scripts we have written are in place to collect data. One of the special scripts connects to Weblogic on each node to capture data from several MBeans. Other scripts watch for problems with hardware, the operating system, database, and even login to Vista. Each server (node or database) has, I think, 30-40 monitors. A portion of items we monitor is in the presentation. Every level of our clusters are watched for issues. The data from these scripts are collected into two applications.

  1. Nagios sends us alerts when values from the monitoring scripts on specific criteria fall outside of our expectations. Green means good; yellow means warning; red means bad. Thankfully none in our group are colorblind. Nagios can also send email and pages for alerts. Finding the sweet spot where we get alerted for a problem but avoid false positives perhaps is the most difficult.
  2. An AJAX application two excellent members of our Systems group created called internallyl Stats creates graphs of the same monitored data. Nagios tells us a node failed a test. Stats tells us when the problem started, how long it lasted, and if others also displayed similar issues.We also can use stats to watch trends. For example, we know two peaks by watching WIO usage rise to a noonish peak slough by ~20% and peak again in the evening fairly consistently over weeks and months.

We also use AWStats to provide web server log summary data. Web server logs show activity of the users: where they go, how much, etc.

In summary, Nagios gives us a heads up there is a problem. Stats allows us to trend performance of nodes and databases. AWStats allows us to trend overall user activity.

Coradiant TrueSight was featured in the vendor area at BbWorld. This product looks promising for determining where users encounter issues. Blackboard is working with them, but I suspect its likely for Vista 4 and CE 6.

We have fantastic data. Unfortunately, interpreting the data proves more complex. Say the load on a server hosting a starts climbing, its the point we get pages and continues to climb. What does one do? Remove it from the cluster? Restart it? Restarting it will simply shift the work to another node in the cluster. Say the same happens with the database. Restarting the database will kick all the users out of Vista. Unfortunately, Blackboard does not provide a playbook on what to do with every support possibility. Also, if you ask three DBAs, then you will likely get three answers.
😀

Its important to balance the underreaction and overreaction. When things go wrong, people want us to fix the problem. Vista is capable of handling many faults and not handling very similar faults. The link example was a failed firewall upgrade. I took a similar tact with another firewall problem earlier this week. I ultimately had to restart the cluster that evening because it didn’t recover.

Part three will discuss the node types.

links for 2007-07-18

.