VirtuallyUseful – Random Tech Babble

January 22, 2012

Limiting vCenter Tomcat Usage

Filed under: vCenter, VMware — Tags: , , — Ray Olander @ 1:33 PM

Information obtained from from http://www.virtualserverguy.com/blog/2011/2/11/limiting-vcenter-tomcat-usage.html

LIMITING VCENTER TOMCAT USAGE

Here is how to limit the memory usage for VMware’s vCenter…

First vCenter relies on a customized Apache Tomcat to run its vCenter product (mostly graphs, Web Interface and other items), while limiting the memory hasn’t proven to have a negative effect this procedure should be done with caution. This can cause slowness in portions of the application since it will no longer be able to store large amounts of data in RAM and will have to access the database for this information.

1. Open Regedit on the vCenter server

2. Navigate to: HKLM\Software\Wow6432Node\Apache Software Foundation\Procrun 2.0\vctomcat\Paramaters\Java

3. Change JvmMS, JvmMX and JvmSs to ‘0’

4. Restart the VMware vCenter WebAccess Service in Windows and enjoy a smaller footprint of the Tomcat process.  The average RAM usage for Tomcat after this change should be around 256MB (plus or minus the amount of VM’s being managed).

Note: This procedure should only be done in test or small environments

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My experience is that when I did this in my lab, memory usage went from 1.2GB to 170MB (3 ESXi hosts and 1 vCenter server). That’s a lot of savings when you only have a small amount of memory available to start with!

January 21, 2012

Converting a Cisco 1242AG lightweight AP to Standalone

Filed under: Cisco, Networking — Ray Olander @ 8:39 PM

So, it turns out that when you have an Cisco access point that starts with AIR-LAP instead of AIR-AP, it is configured to attach to a wireless controller on your network before it does anything useful. If you don’t happen to have a Cisco Wireless Controller configured and on your network to handle that, your access point is essentially a very expensive paper weight…or is it?!

It turns out that you can convert the AP from lightweight mode to standalone mode (and vice-versa actually).  I am going to list the steps I took to do this because I didn’t find any articles on the Internet to tell me how, but don’t let this fool you – I am not a Cisco guy. If I didn’t write it down here, I likely don’t have any additional answers on this topic other than “if it doesn’t work, get a bigger hammer” :)

So here we go:

PC Setup

Download TFTPD (TFTP server) and configure to point to some directory (which will be your “base” directory) and to allow it to operate through your firewall.

Download IOS software for the 1242 (I used c1240-k9w7-mx.124-25d.JA1 for this experiment)

Make a copy of the IOS file named “c1240-k9w7-tar.default” in the TFTP base directory (The AP will look for this exact file name)

Download and run Putty. Create a session to COM1 9600/8-N-1 (I turn on logging and set the scrollback buffer to 9999 lines)

Configure a PC for 10.0.0.2/255.0.0.0 and either connect to a switch dedicated for this purpose or use a crossover cable (the AP will default to 10.0.0.1)

Connect the Cisco blue console cable between COM1 on the PC and the console port on the AP

Open the Putty COM1 session to monitor the AP when it comes up

AP setup

Connect 2GHz (cone shaped) and 5GHz (flat) antennas to the appropriate connectors on the AP

Connect the access point to a switch or crossover cable

Load new IOS on AP

Press and hold the MODE button and plug in the power

When you see “Button is pressed, wait for button to be released” in your Putty session, let go of the button

The AP will startup, default to 10.0.0.1 and look for a TFTP server that has “c1240-k9w7-tar.default” ready to serve

The AP will automatically download the new IOS and delete the lightweight image (mine was “c1240-rcvk9w8-mx”)

You should see something like “Download default IOS tar image tftp://10.0.0.2/c1240-k9w7-tar.default”

Once the AP has fully started, do the following to get the Ethernet interface activated

ap>en

Password: Cisco (this is case sensitive)

ap# config t

ap(config)# interface FastEthernet 0

ap(config)# ip addr 10.0.0.1 255.0.0.0 (or perhaps what IP it will eventually have on your production network)

ap(config)# interface BVI1

ap(config)# ip addr 10.0.0.3 255.0.0.0 (same network as the Ethernet interface)

press ctrl+z to exit config

type wr to write the config

Go to your PC and open http://10.0.0.1 to get to the web interface of the AP to finish configuring the device.

The username is Cisco and the password is Cisco (both are case-sensitive)

If you changed the IP address to something other than 10.0.0.1 & 10.0.0.3 above, be sure to change your PC IP address too before trying to access the configuration webpage.

I hope this helped someone!

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