nothing is impossible!!!!

nothing is impossible!!!!

Tuesday, June 15, 2010

firefox and java plugin on linux

1. Download jre-6u20-linux-x64.bin

2. ./jre-6u20-linux-x64.bin

3. ln -s /tmp/jre1.6.0_21/lib/amd64/ /usr/lib/mozilla/plugins/

4. ls -al /usr/lib/mozilla/plugins/

Monday, June 14, 2010

update rhel4 packages

You can use "update -u" to update the packages on RHEL4.

If it does not give you any indication of package updation try to clear cache (rm -rf /var/spool/up2date/*) and fire above command again.

Even if above method doesnt work. Login to your respective rhn satellite.
1. Select Critical, Non-critical packages.
2. Select All.
3. at the bottom, select update packages
4. then confirm.
5. ssh to the respective system, and run "rhn_update -vvv". It should show updating package details.

Monday, April 26, 2010

Good article on iscsi

Thursday, April 15, 2010

How to select specific storage ?

What is largest amount of data do you manage?

How much data is significant for you?

have you planned about deletion of data?

how ofter will you delete data? schedule?

Who is gone access your data? ex. applications, servers ?

are you planning to host your applications as well?

how must data application gone consume?

how much your application data may grow?

How busy will be your storage?

applications future plans?

How much data may grow in future?

If data not available, how does unavailability cost your org?

are you planning to archive data?

Why do you want to archive data?

how ofter are you planning to archive data?

for how long will you keep archive data?

existing data managements issues?

data center to manage data storage equipment?

Enough space in datacenter?

Tuesday, April 13, 2010

kickstart fully automatic installtion for rhel

Note: Please remember options may vary depend on OS, network settings, os update version etc.

This fully automatic installation cfg is for RedHat 5 OS.

nfs --server= --opts=tcp --dir=/pub/rhel/released/RHEL-5-Client/U5/i386/os
keyboard us
lang en_US
key --skip
reboot --eject
selinux --disabled
firewall --disabled
rootpw redhat

timezone --utc Asia/Kolkata
network --onboot yes --bootproto dhcp --gateway --nameserver

#Setup default services
services --disabled=cups,messagebus,ip6tables,isdn,pcmcia,hidd,bluetooth --enabled=ntpd,nscd

# Disk Setup

bootloader --location=mbr --append="rhgb console=tty0 console=ttyS0,9600"
clearpart --all

# auto disk partition
part /boot --fstype ext3 --size=100
part swap --fstype swap --size=2048
part pv.1 --size=0 --grow
volgroup AutoVolGroup pv.1
logvol / --vgname=AutoVolGroup --name=root --size=1 --grow


cat <> /etc/motd
Lab automatic kickstart installation.
Installed `date`
cat /etc/motd >> /root/ks.cfg

Wednesday, April 7, 2010

disable selinux on the fly

To disable selinux on the fly you should run following command in terminal,
setenforce 0

to disabled it permanently, open /etc/selinux/config and change value to SELINUX=disabled

Friday, February 19, 2010

How to upgrade firmware on Dell DRAC?

DRAC stands for Dell Remote Access Controller. The DRAC on current models is a separate chipset and board that is connected to the server main board with its own network interface as well as a direct configuration accessible during system initialization.

DRAC has a default TCP/IP address and can be change during system initialization

I found dmidecode currently does not return any information about DRAC card on the system. If you have system tag with you can check online if systems include DRAC card.
* Put you system tag here,
* Click on "Original System configuration"
* Search for "DRAC"

Here is firmware upgrade process.

* Download the firmware for your system, In my case it was Power Edge 2950 system. I found firware versions here.

* Download windows zipped exe file and extract it.There should be only one file named "firmimg.d5".

* Copy the same to your tftp server at /tftpboot/pxelinux.cfg/ location. (Can share it and mount on tftpserver or use WinSCP to copy files to remote unix system)

* Login to drac server using the IP assigned to DRAC.
Before upgradation firmware version

[root@npatil ~]# ssh drac-ip
root@drac-ip's password:

Dell Remote Access Controller 5 (DRAC 5)
Firmware Version 1.0 (Build 06.05.12)

$ racadm fwupdate -g -u -a tftpserver-ip-address -d firmimg.d5
Firmware update completed successfully. The RAC is in the process of
resetting. Please wait up to a minute for this to complete.

Please do not make any changes in DRAC configuration while doing firmware upgradation.

It may disturb upgrade process.

After upgradation Firmware Version

[root@npatil ~]# ssh drac-ip
root@drac-ip's password:

Dell Remote Access Controller 5 (DRAC 5)
Firmware Version 1.20 (Build 07.03.02)

Sunday, February 7, 2010

SAN terminologies

Here I am trying to put every definition related to SAN on single page. Its a collective information from different sites.

AoE: ATA over Ethernet: its a network protocol designed to access SATA storage devices over the Ethernet networks. AoE does not rely on network layers above Ethernet, such as IP and TCP.
The advantage of AoE is that you don't have the overhead of translating ATA to SCSI and then back to ATA (if you are using ATA drives). So there is a performance pickup.

NBD: The Linux Network Block Device (NBD) is a device driver extension to the Linux kernel. With the NBD device driver you can create a TCP/IP network connection between your local Linux system and a server program on a remote (not necessarily Linux) computer. But NBD has some limitations in terms of read/write operation and using NBD as a root file system.
Server processing load for iSCSI is much higher than AoE for equivalent throughput. AoE can spare processing cycles. iSCSI requires TCP/IP and its requisite complexity.

ENBD- Enhanced Network Block Device
GNBD- Global Network Block Device

WWPN: World Wide Port Name. A globally unique identifier for a port which allows certain applications to access the port. The FC switches discover the WWPN of a device or host and assign a port address to the device.

Multipathing: When transferring data between the host server and storage, the SAN uses a multipathing technique. Multipathing allows you to have more than one physical path from the Server host to a LUN on a storage array.
If a default path or any component along the path—HBA, cable, switch port, or storage processor—fails, the server selects another of the available paths. The process of detecting a failed path and switching to another is called path failover.

An active/active disk array, which allows access to the LUNs simultaneously through all the storage processors that are available without significant performance degradation. All the paths are active at all times (unless a path fails).

An active/passive disk array, in which one SP is actively servicing a given LUN. The other SP acts as backup for the LUN and may be actively servicing other LUN I/O. I/O can be sent only to an active processor. If the primary storage processor fails, one of the secondary storage processors becomes active, either automatically or through administrator intervention.