Author Archives: Bastiaan van Leeuwen

Performance Troubleshooting for VMware vSphere 4

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Performance problems can arise in any computing environment. Complex application behaviors, changing demands, and shared infrastructure can lead to problems arising in previously stable environments. Troubleshooting performance problems requires an understanding of the interactions between the software and hardware components of a computing environment. Moving to a virtualized computing environment adds new software layers and new types of interactions that must be considered when troubleshooting performance problems.

The attached document is the first installment in a guide covering performance troubleshooting in a vSphere environment. It uses a guided approach to lead the reader through the observable manifestations of complex hardware/software interactions in order to identify specific performance problems. For each problem covered, it includes a discussion of the possible root-causes and solutions. Topics covered include performance problems arising from issues in the CPU, memory, storage, and network subsystems, as well as in the VM and ESX host configuration. Guidance is given on relevant performance metrics to observe using the vSphere Client and esxtop in order to isolate specific performance issues.

This first installment of Performance Troubleshooting for VMware vSphere 4 covers performance troubleshooting on a single VMware ESX 4.0 host. It focuses on the most common performance problems which affect an ESX host. Future updates will add more detailed performance information, including troubleshooting information for more advanced problems and multi-host vSphere deployments.

vsphere4-performance-troubleshooting.pdf

source

Create user account in Symantec System Center 10.x

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To create a user account for a server group

  1. Start Symantec System Center.
  2. Right-click the appropriate server group.
  3. Click Account Management.
  4. In the Configure Server Group Accounts dialog box, click Add.
  5. In the Account Setup dialog box, do the following:
    • Type the user name.
    • In the New password box, type the password.
    • In Confirm password box, type the password again.
    • Under Account Type, check the role that you want to assign to the user: Read-only, Administrator, Central Quarantine, or Gateway Security.
  6. Click OK.
  7. Click Finished.
    The changes are then sent to the secondary management servers in the server group.

source

How to change the password in Symantec AntiVirus Corporate Edition 10.x

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Document ID: 2005041217010148

About the server group password
The “Remember this user name and password for me” check box saves a password so that you do not have to enter it the next time the server group is opened. Also, if you “Automatically unlock this Server Group when I start the Symantec System Center,” the password is saved in a secured cache.

To no longer save the server group password

  1. In the Symantec System Center console, in the left pane, right-click a locked server group, and then click Unlock Server Group.
  2. Uncheck Remember this user name and password for me.
  3. Uncheck Automatically unlock this Server Group when I start the Symantec System Center.
  4. Click OK.
  5. Exit the Symantec System Center console.
  6. When you are prompted to save, click No.

The server group is now configured to prompt for a password, and the server group will not be unlocked automatically when you start Symantec System Center.

Reset the Symantec System Center admin user password
You can use the Password Reset Utility to reset any user’s password. You must have Administrator access to the primary server of the server group.

To reset the Symantec System Center admin user password

  1. On the computer running Symantec System Center, start Windows Explorer.
  2. Go to \Program Files\Symantec\Symantec System Center\Tools.
  3. In the right pane, double-click the IFORGOT.exe file.
  4. In the Primary server field, type the name of the server group’s primary server.
  5. In the user field, type admin
  6. In the New Password and Confirm New Password fields, type the new password.
  7. Click Reset Password.
    You may be prompted for a Windows user name and password if you specify a remote server.

For information about creating and managing user accounts in Symantec System Center, see the document Using Symantec System Center roles in Symantec AntiVirus 10.x and Symantec Client Security 3.x.

Use a client uninstallation password
It is possible to configure the client component of Symantec AntiVirus to request a password before allowing a user to uninstall it. By default, this feature is enabled, but often the password is not set by an administrator. When the client can communicate with the server, the password can be reset or disabled.

To require a password before uninstalling

  1. In the Symantec System Center console, right-click a server, a server group, or a client group, and then click All Tasks > Symantec AntiVirus > Client Administrator Only Options.
  2. On the Security tab, check Ask for password to allow uninstall of Symantec AntiVirus Client.
  3. Click Change.
  4. In the Configure Password dialog box, type a new password, and then confirm by typing the password again.
  5. Click OK, and then click OK again.

If the client system needs to be uninstalled but can no longer communicate with the parent server, please contact Symantec Technical Support for assistance.

Use a client network scan password
In a networked environment where most, if not all systems are running some form of antivirus software, it is inefficient to allow the systems to perform real-time or manual scanning of network resources. In such a setting, the network resources are already protected by the local antivirus system. However, it may not be desirable to completely disable this functionality as you may want to remote scan a system at a later date. The best solution is to implement a password known only to the system administrators that prevents casual scanning of network resources, while leaving it available as a useful tool. If the client system can still communicate with the parent server, the password can be reset or disabled.

To require a password before uninstalling

  1. In the Symantec System Center console, right-click a server, a server group, or a client group, and then click All Tasks > Symantec AntiVirus > Client Administrator Only Options.
  2. On the Security tab, check Ask for password to allow scan of Mapped Network Drives.
  3. Click Change.
  4. In the Configure Password dialog box, type a new password, and then confirm by typing the password again.
  5. Click OK, and then click OK again.

Install windows 2003 Server on a Dell Latitude E6500

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When you try to install windows 2003 server onto a dell laptop, it will crash during the dos setup.

This is because the Hard disk mode has the wrong type. Change the hard disk mode in the bios of the system to ATA and try again.

When booting press F12
Select BIOS
Change Hard disk mode to ATA
Reboot, and install Windows 2003 Server

CentOS install and configure NTP to synchronize the system clock

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Type the following command to install ntp:

[root@myServer ~] # yum install ntp

Turn on the service

[root@myServer ~] # chkconfig ntpd on

Synchronize the system clock with pool.ntp.org server:

[root@myServer ~] # ntpdate pool.ntp.org

Start the ntp:

[root@myServer ~] # /etc/init.d/ntpd start

Check the time:

[root@myServer ~] # date

Check if the bios clock matches the system clock:

[root@myServer ~] # hwclock

Set the bios clock to match the system clock

[root@myServer ~] #hwclock --systohc

Set the ntp time servers in the file /etc/ntp.conf (the ntp servers will begin with: server)

CentOS Firewall

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Activating the IPTables Service

The firewall rules are only active if the iptables service is running. To manually start the service, use the following command:

[root@myServer ~] # service iptables restart

To ensure that iptables starts when the system is booted, use the following command:

[root@myServer ~] # chkconfig --level 345 iptables on

The ipchains service is not included in Red Hat Enterprise Linux. However, if ipchains is installed (for example, an upgrade was performed and the system had ipchains previously installed), the ipchains and iptables services should not be activated simultaneously. To make sure the ipchains service is disabled and configured not to start at boot time, use the following two commands:

[root@myServer ~] # service ipchains stop
[root@myServer ~] # chkconfig --level 345 ipchains off

 

Using IPTables

The first step in using iptables is to start the iptables service. Use the following command to start the iptables service:

[root@myServer ~] # service iptables start

 

Show current IPTables config

To show all current settings in the IPTables program, execute the following command:

[root@myServer ~] # iptables –L

 

IPTables Command Syntax

The following sample iptables command illustrates the basic command syntax:

[root@myServer ~ ] # iptables -A <chain> -j <target>

The -A option specifies that the rule be appended to <chain>. Each chain is comprised of one or more rules, and is therefore also known as a ruleset.

The three built-in chains are INPUT, OUTPUT, and FORWARD. These chains are permanent and cannot be deleted. The chain specifies the point at which a packet is manipulated.

The -j <target> option specifies the target of the rule; i.e., what to do if the packet matches the rule. Examples of built-in targets are ACCEPT, DROP, and REJECT.

Important

When creating an iptables ruleset, order is important.

If a rule specifies that any packets from the 192.168.100.0/24 subnet be dropped, and this is followed by a rule that allows packets from 192.168.100.13 (which is within the dropped subnet), then the second rule is ignored.

The rule to allow packets from 192.168.100.13 must precede the rule that drops the remainder of the subnet.

To insert a rule in a specific location in an existing chain, use the -I option. For example:

[root@myServer ~ ] # iptables -I INPUT 1 -i lo -p all -j ACCEPT

This rule is inserted as the first rule in the INPUT chain to allow local loopback device traffic.

 

Saving and Restoring IPTables Rules

Changes to iptables are transitory; if the system is rebooted or if the iptables service is restarted, the rules are automatically flushed and reset. To save the rules so that they are loaded when the iptables service is started, use the following command:

[root@myServer ~ ] # service iptables save

The rules are stored in the file /etc/sysconfig/iptables and are applied whenever the service is started or the machine is rebooted.

Documentation

IPTables: http://wiki.centos.org/HowTos/Network/IPTables

Firewalls: http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-fw.html

Linux: Setup as DNS Client / Name Server IP Address

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Many new Linux user finds it difficult to setup / modify new name server address (NS1 / NS2).

Local name resolution is done via /etc/hosts file. If you have small network, use /etc/hosts file. DNS (domain name service is accountable for associating domain names with ip address, for example domain yahoo.com is easy to remember than IP address 202.66.66.12) provides better name resolution. To configure Linux as DNS client you need to edit or modify /etc/resolv.conf file. This file defines which name servers to use. You want to setup Linux to browse net or run network services like www or smtp; then you need to point out to correct ISP DNS servers:

/etc/resolv.conf file

In Linux and Unix like computer operating systems, the /etc/resolv.conf configuration file contains information that allows a computer connected to the Internet to convert alpha-numeric names into the numeric IP addresses that are required for access to external network resources on the Internet. The process of converting domain names to IP addresses is called “resolving.”

The resolv.conf file typically contains the IP addresses of nameservers (DNS name resolvers) that attempt to translate names into addresses for any node available on the network.

Setup DNS Name resolution

Steps to configure Linux as DNS client, first login as a root user (use su command):

Step # 1: Open /etc/resolv.conf file:

# vi /etc/resolv.conf

Step #2: Add your ISP nameserver as follows:

search isp.com
nameserver 202.54.1.110
nameserver 202.54.1.112
nameserver 202.54.1.115

Note Max. three nameserver can be used/defined at a time.

Step # 3:Test setup nslookup, dig or host command:

# dig www.google.com
# nslookup www.google.com
# host www.google.com

CentOS Configuring Proxy Server Access for Yum

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To enable all yum operations to use a proxy server, specify the proxy server details in /etc/yum.conf. The proxy setting must specify the proxy server as a complete URL, including the TCP port number. If your proxy server requires a username and password, specify these by adding proxy_username and proxy_password settings.

The settings below enable yum to use the proxy server mycache.mydomain.com, connecting to port 3128, with the username yum-user and the password qwerty.

# The proxy server - proxy server:port number
proxy=http://mycache.mydomain.com:3128
# The account details for yum connections
proxy_username=yum-user
proxy_password=qwerty

Howto Install vmware tools in Ubuntu

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source: http://www.ubuntugeek.com/howto-install-vmware-tools-in-ubuntu.html

We have already discussed about VMware server setup in gutsy.Now It is very important that you install VMware Tools in the guest operating system.With the VMware Tools SVGA driver installed, Workstation supports significantly faster graphics performance.The VMware Tools package provides support required for shared folders and for drag and drop operations.

Other tools in the package support synchronization of time in the guest operating system with time on the host, automatic grabbing and releasing of the mouse cursor, copying and pasting between guest and host, and improved mouse performance in some guest operating systems.

Click on VM in the top menu of the VMware Server console and select Install VMware Tools.

 Now you should be able see the following screen here click on install

 Now you should see similar to the following screen on your desktop

 First copy the VMware Tools from the mounted iso to the temporary folder

cp /media/cdrom/VMwareTools-1.0.3-44356.tar.gz /tmp/

Afterwards switch to the temporary folder and unpack the VMware Tools:

cd /tmp/

tar xvfz VMwareTools-1.0.3-44356.tar.gz

Next switch to the folder with the unpacked files and execute the installer:

cd vmware-tools-distrib/

sudo ./vmware-install.pl

Now you will be asked a few questions relating to installation paths etc. Choose the default value every time (simply hit enter).

 After the installation/configuration finished you have to start the VMware Tools:

vmware-toolbox &

Once it opens you should be able to see similar to the following screen

Vmware tools version details

Note: If you close the VMware Tools window, the VMware Tools will be disabled immediately.