Easiest way to calculate SAN data transfer rate from AIX

In order to check how much data throughput speed from your FC connections of AIX servers to any san attached storage

1. Identify any filesystem , created on any vg residing on SAN disks ( let say /data1)

2. time dd if=/dev/zero of=/data1/testfile bs=32768 count=30000

It will create around 10 GB file in /data1 so make sure you have enough space there. After getting value of time period required to copy such file , you can divide this size by time to get the data transfer speed in Mb/Sec.

For example , if real time value returned by time command output results around 1 min so value of data transfer would be 10x1024/60= 170 Mb/sec.

VSCSI disks mapping to Physical disks AIX VIO

The other day , during one implementation of a project , i stuck on a silly point.

I was implementing Oracle RAC on two P570 servers which are located on distant sites and fully virtualized through dual VIO configuration. We assigned many disks from DS6000 to VIO servers and name these disks according to naming convention required by Oracle DBA. For example virtual disk for second voting disk as required by Oracle DBA was named on VIO servers as "lparnamevtdisk2"...

We ensured that we configured correct disk for correct purpose by executing these two following commands
# oem_setup_env
# datapath device 13 ( as we were using SDDPCM /AIX MPIO on VIO servers).

Now but we went back to AIX client Lpars and executed cfgmgr, we were able to get large number of disks , but got confused as apparanetly all these disks are vscsi disks and dont have any serial number which can matched with SAN Lun Serial numbers...

Then after some research , i got following information that in order to map virtual scsi disks on AIX client Lpars with original physical disks , you have to execute

#lscfg -vl hdiskxx ( on AIX client Lpar ) and note down serial number ( which could be something like L86xxxx) and then you have to go to VIO partition and then check for same serial number on virtual disks devices with command lsmap -all or if you know exact vhost for your client Lpar you can also use lsmap | grep vhostx.

Guys! I am Back....

Guys,

Sorry i was away for almost more than one month on annual vacations so could'nt update my blogs for a while .. Now i am back... so you can expect some new material very soon on my web site...

Wpars versus Lpars- A quick comparision

While Lpars and Wpars are both virtualization features of IBM Power systems , there are inherently differences which do reside between Lpars and Wpars.

I would say a major difference which exist between Lpars and Wpars is that Lpars are hardware based virtualization approach while Wpars are software based approach.
WPARs are lightweight and quicker to install, because they share many of the file systems and resources of the global AIX system in which they reside.
On the other hand While using an LPAR requires you to install an entire operating system, creation of system WPARs only installs private copies of a few file systems, and application WPARs share even more of the global system's resources. As a result, a WPAR can be created in just a few minutes without installation media. Ongoing administration and maintenance of WPARs should be simpler—fewer AIX licenses might be required, and you don’t have to install fixes and updates on so many virtual systems. There is a command for synchronizing the filesets of a WPAR with the corresponding filesets on the global system, so you have the choice of propagating AIX fixes to WPARs or continuing to run with the current versions of system files.

While LPARs offer a significantly higher degree of workload isolation, WPARs might provide "good enough" isolation for your particular workloads, especially temporary ones such as development or test environments. Similarly, with LPARs, you can achieve a greater degree of control over the usage of resources—by allocating entire processors or precise fractions of processors to an LPAR, for example. With WPARs, you don’t have such fine control over resource allocations, but you can allocate target shares or percentages of CPU utilization to a WPAR (if have used the AIX Workload Manager, you will find the share and percentage resource allocation scheme familiar). Similar differences exist for the allocation of memory, number of processes, and other resources.

NPIV or Virtual SCSI- Which one is better?

Last days i was investigating about real difference between NPIV and Virtual SCSI options available on IBM Pseries platform for virtualisation implementation.Unfortunately i could not find that except that if you have a FC based tape library or any other tape device and you want to share it between your Lpars ( which is rear case in today's market as it is captured by enterprise backup solutions like TSM or Veritas which does not require this kind of setup) or when you want to avoid word SCSI in front of your management, you can opt NPIV approach otherwise vscsi approach is well established approach in terms of performance ad reliability.

However , for NPIV , following are minimum requirements:

1. Eight Gig FC Adapater ( NPIV capable)

2. NPIV capable SAN switches

3. VIO 2.1

So rule of thumb is that if you dont have above mentioned luxuries , you can stick to VSCSI approach.

World cup hockey 2009 - Qualifying Round France

Qualifying tournament for World cup hockey 2010 is currently being played in Lille France. as it is

Our team , Pakistan Hockey team ( so called Green shirts ) have played nicely till date and they have won all three matches against Russia,France and Italy by quite big margin. It is a good news for hockey lovers in Pakistan but in my view until and unless Pakistani boys do not won the final of this tournament , we should not be so much happy. Reason being our team has played very good in some other recent tournaments , but loose their spirits in final match. Now , here in Lille, there is no such chance for pakis. They will play 2010 world cup hockey if and only if they win this tournament.

Good news is that sohail Abbas is scoring good on penality corners. This is a healthy sign.
I hope that inshallah , Pakistani team will win this very important tournament as it is do or die situation for game of hockey in Pakistan

Another good thing about this tournament is that FIH is covering well this tournament.Highlights of all matches are available on youtube and also on following web site

http://www.worldcupqualifiermenfrance.sportcentric.com/vsite/vcontent/page/custom/0,8510,5227-199239-216462-47641-301903-custom-item,00.html

AIX 32 and 64 bit Dilemma

Software requirement for 64 bit AIX OS

Beside hardware requirement for running 64 bit operating system on IBM POWER systems , the other main requirement is fileset.The bos.64bit is the Base Operating System 64-bit runtime fileset. If bos.64bit is not installed, you do not have the /etc/methods/cfg64 file. Without the /etc/methods/cfg64 file, you will not have the option of enabling or disabling the 64-bit environment via SMIT, which updates the inittab with the load64bit line (simply adding this line does not enable the 64-bit environment).

The command lslpp -l bos.64bit will reveal if this fileset is installed. The
bos.64bit fileset is on the 4.3.x media, however, installing it does not ensure
that you will be able to run 64-bit software.

With the bos.64bit fileset installed on non 64-bit hardware, you should be able
to compile your 64-bit software; however, you will not be able to run 64-bit
programs on your 32-bit hardware.



Hardware required

You must have 64-bit hardware to run 64-bit applications. At AIX levels 4.3.2
and 4.3.3, to determine whether your system has 32-bit or 64-bit hardware
architecture:

Log in as root.
At the command line, enter:
bootinfo -y

This produces the output of either 32 or 64, depending on whether the hardware
architecture is 32-bit or 64-bit.

In addition, if you enter lsattr -El proc0, at any version of AIX, the output of
the command should return the type of processor for your server.

The types of 64-bit processors are as follows:

PowerPC_RS64
PowerPC_RS64 II
PowerPC_RS64 III
PowerPC_Power3
PowerPC_Power3 II



Kernel extensions vs. 64-bit kernel

To determine if the 64-bit kernel extension is loaded, from the command line
enter:

genkex |grep 64

You should see information similar to the following:

149bf58 a3ec /usr/lib/drivers/syscalls64.ext

NOTE: Having the driver extensions, does not mean that the kernel is a 64-bit
kernel. A 64-Bit Kernel became available at 5.1 oslevel.

The driver extensions just allows the 64-bit application to be compiled by a
32-bit kernel. If the 32-bit kernel has a 64-bit processor, the syscalls64.ext
will allow the 64-bit application to execute. Yet at 5.1, a 64-bit kernel and a
64-bit processor has better performance with 64-bit applications.

To truly change the kernel to 64-bit, you need to be at the 5.1 oslevel. The
means to change to a 64-bit kernel are:

From 32-bit to 64-bit:

ln -sf /usr/lib/boot/unix_64 /unix
ln -sf /usr/lib/boot/unix_64 /usr/lib/boot/unix
lslv -m hd5
bosboot -ad /dev/ipldevice
shutdown -Fr
bootinfo -K (should now be 64)

To change the kernel back to 32-bit:

From 64-bit to 32-bit:

ln -sf /usr/lib/boot/unix_mp /unix
ln -sf /usr/lib/boot/unix_mp /usr/lib/boot/unix
lslv -m hd5
bosboot -ad /dev/ipldevice
shutdown -Fr
bootinfo -K (should now be 32)


32-bit and 64-bit performance comparisons on IBM POWER systems

To examine the benefits and drawbacks of going from 32-bit to 64-bit mode and
further effects on the system, consult the following, AIX 64-bit Performance in
Focus, which is available at IBM Redbooks.

In most cases, running 32-bit applications on 64-bit hardware is not a problem,
because 64-bit hardware can run both 64-bit and 32-bit software. However, 32-bit
hardware cannot run 64-bit software. To find out if any performance issues exist
for applications that are running on the system, such as Lotus Notes and Oracle,
refer to those application's user guides for their recommended running
environment.