Installing Cassandra in Windows

Installing Cassandra Project (http://cassandra.apache.org/)on Windows is really simple, maybe more the do it on Linux.

Cassandra is a BD engine written in Java, the only requirements to install it is Java 1.6 (Is better to use the most up-to-date version).

After installing Java, download the tar.gz archive for the official site and then untar it in the chosen folder (For this example we use "C:\Cassandra").

Well, now just do a bit of configuration. Open "C:\Cassandra\conf\storage-conf.xml" and change default value of the nodes below to:

<commitlogdirectory>C:\Cassandra\commitlog</commitlogdirectory>
<datafiledirectories>
<datafiledirectory>C:\Cassandra\data</datafiledirectory>
</datafiledirectories>

Note: normally is better to use two different disks for commit logs and datas.


Finally, we have to set "CASSANDRA_HOME" as system variable with value "C:\Cassandra"

So, now we can launch "C:\Cassandra\bin\cassandra.bat" to start the Cassandra Server.

Ok, at this point the Cassandra server will be "up-n-running".


To test it, we can launch "C:\Cassandra\bin\cassandra-cli.bat" and then give the command:

connect localhost/9160

If all works, we'll have this answer: "Connected to: "Test Cluster" in localhost/9160"

Enjoy :)

Create a link from command prompt

To create a link to a file or a folder we generally use the GUI. For particular issues (script, batch files) is possible to use shell commands.

Commands are:

mklink "Link Name" c:\Folder\SubFolder\filename.txt

or

mklink "Link Name" c:\Folder\SubFolder


These commands create a link called "Link Name" that refers to the specified folder or file.

Warning: the link will be created in the folder where the command runs.

Windows 7 God Mode

Windows 7 (and also Windows Vista) has an hidden mode called "God Mode". With a small trick is possible to have access to an "Extended Control Panel" with a lot of functions.

I'm speaking about all the personalisation that Microsoft use for their Operating sistems. So, no filters!

The procedure is simple: just create a new folder on the desktop and rename it in:

GodMode.{ED7BA470-8E54-465E-825C-99712043E01C}

At this point a shortcut icon should appears. This icon opens a Grafical Interface for the "God Mode". There is an issue: this trick may not work properly with 64 bit os versions.

VMware error: "Another task is already in progress"

Sometimes, in VMware ESX 3.5 and vSphere 4.0, when you try to perform some actions against a virtual machine (like for example to take a snapshot or to rename it) the system throw an exception with the message "Another task is already in progress" even if there are no active tasks.

The solution is to ssh to the physical ESX server that the virtual machine resides on and restart the “mgmt-vmware” service as the user root.

service mgmt-vmware stop
    Stopping VMware ESX Management services:
    VMware ESX Host Agent Watchdog [ OK ]
    VMware ESX Host Agent [ OK ]

Wait 30 seconds and start the service

service mgmt-vmware start
    Starting VMware ESX Management services:
    VMware ESX Host Agent (background) [ OK ]
    Availability report startup (background) [ OK ]

The ESX server and any virtual machines hosted on it will disconnect from the Virtual Infrastructure/vSphere Client and can be reconnected by right clicking on the ESX server and choosing “reconnect”.

When it reconnects attempt the tasks that were failing earlier and they should now as intended.

Exchange 2007 Message Size Limit

In Microsoft Exchange 2007 you have 10Mb limit for messages size. To increase this limit, you have to do several configurations.

After setting the single user mailbox limit from the GUI (Exchange Management Console), go to the shell (Exchange Management Shell) and type the commands below. Uppercase commands print the configuration parameters, "set" commands modify the values.


GET-TRANSPORTCONFIG

set-transportconfig -MaxReceiveSize VALUE
set-transportconfig -MaxRecipientEnvelopeLimit VALUE
set-transportconfig -MaxSendSize VALUE


GET-RECEIVECONNECTOR LIST

set-receiveconnector -MaxMessageSize VALUE (if requested, the "identity" are listed by the upper command)


GET-SENDCONNECTOR LIST


set-sendconnector -MaxMessageSize VALUE (if requested, the "identity" are listed by the upper command)



VALUE can be expressed, for example, like 10000 or 10MB