Archive for February, 2008

Raw Devices on RHEL 5 or OEL 5

Posted on February 15, 2008. Filed under: Linux | Tags: , , , , |

Be aware that raw device technology had been deprecated in RedHat Linux 5 (RHEL5) and Oracle Enterprise Linux 5 OEL5). / Linux Kernel 2.6
Does this mean we cannot use Rawdevices in RHEL5 or OEL5? As always there’s a workaround to make this happen by means of UDEV technique and Oracle 11g & 10gR2 has options to configure components to access the block devices directly instead of rawdevices.
Before we jump into the workaround, let see what exactly is missing at the O/S level w.r.to rawdevices in RHEL5 and OEL5,

  1. /etc/sysconfig/rawdevices file doesn’t exist
  2. /dev/raw doesn’t exist.
  3. Service by the name “rawdevices” doesn’t exist.

Trying to run the command “service rawdevices restart” will result in “rawdevices: unrecognized service”.

Now lets see an example of configuring rawdevices in RHEL4 and RHEL5.

RHEL4

To map a rawdevice to a block device /dev/sdf1

Step 1: Make an entry in /etc/sysconfig/rawdevices file

/dev/raw/raw1 /dev/sdf1

Step 2: For the mapping to have immediate effect, restart the rawdevices service.

$>service rawdevices restart

Step 3: Change ownership to oracle user

$>chown oracle:dba /dev/raw/raw1

RHEL5 / OEL5

Step 1: Make an entry in /etc/udev/rules.d/60-raw.rules or create your own file viz., /etc/udev/rules.d/<any_no_above_60>-oracle-raw.rules (eg. 63-oracle-raw.rules)

ACTION==”add”, KERNEL==”sdf1″, RUN+=”/bin/raw /dev/raw/raw1 %N”

Step 2: For the mapping to have immediate effect, run below command

$>/bin/raw /dev/raw/raw1 /dev/sdf1

So if you or your system administrator have plans to upgrade an existing release of RHEL or OEL to RHEL5 / OEL5 or planning to perform a new installation of RAC on RHEL5 / OEL5, wherein rawdevices will be / are used, please do take additional care.

For more information you can refer to following
Metalink notes

RAC FAQ: 220970.1 (look for “What storage option should I use for RAC 10g on Linux? ASM / OCFS / Raw Devices / Block Devices / Ext3 ?”)
How to map raw device on RHEL5 and OEL5 – Note 443996.1
Linux 2.6 Kernel Deprecation Of Raw Devices – Note:357492.1
How to install Oracle Clusterware with shared storage on block devices – Note:401132.1

Blogs / Forums
http://frits.homelinux.com/wordpress/?p=27 – Thanks to Frits Hoogland for sharing this information and also for the article on configuring 11g with ASM on CentOS on VMware.
http://www.webservertalk.com/archive221-2007-5-1884747.html – Thanks to Rupan for the explanation on Rawdevices and Block Devices.

cheers,
OraclePitStop

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Uninstall vmware on Windows Vista

Posted on February 9, 2008. Filed under: Vmware | Tags: , |

Uninstalling vmware workstation or servers on Windows vista OS can turn out to be a painful task esp. while trying with control panel -> add / remove programs.

I tried installing VMware workstation 5.5 on Windows Vista Home Premium Edition (for RAC and 11i/R12 installation). The installation went through fine, but when i tried launching the workstation, it errored out stating this release is not supported with Windows Vista. So obviously i tried uninstalling and all i could get is a blue screen. Trying to uninstall again resulted in a blue screen. After some googling and searching i came to know that Vmware Server 1.03 and VMWare Workstation 6 and above are the only supported versions of VM Ware that can be installed on Windows Vista. 

Ok coming back to the problem, as i said the traditional way of uninstalling vmware workstation from Control panel didnt work for me, i even tried removing the entries manually from the registry, but i still had the issue like left over VMWare services like VMware Authorization service, blah blah blah. Heres the link to the article which helped me to solve the problem. Thanks to Lee Lang.
Heres the solution:

Run these commands from your DOS command prompt: 

VMware-workstation-5.5.0-18463 /?  =  will provide you with the list of available options

VMware-workstation-5.5.0-18463 /c = will remove the existing vmware licenses and registration information stored in registry viz., HKEY_LOCAL_M/Software/VMware,Inc./VMware Workstation.

Woila … issue resolved. Tip: You can use the same vmware workstation executable (in my case vmware workstation 5.5) or next higher version (vmware workstation 6) to remove left over vmware products on the system. And dont forget to reboot your system before installing the new release of VMware server/workstation.

cheers,
OraclePitStop

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