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are you looking for AIX administrator?

A colleague and a friend of mine who is a certified AIX/HACMP/VIO/TSM administrator with many years of experience is looking for a new opportunity (preferably in the north-east USA).

If you need an experienced AIX administrator who by the way also knows SAN and VMS then please leave me a comment with your name and email address and/or your cell.
Your “comment” will be 100% private.

Thanks,

MarkD 😀

Posted in Real life AIX.


SDDPCM – change fscsi? attributes without a reboot

It is not difficult to change attributes of a “child” of a fibre channel (FC) adapter (fscsi) operating in the sddpcm environment. The procedure show bellow does not require a host reboot or application downtime.

20% off $75, 25% off $125, 30% off $150 at Sierra Trading Post. Use code: ALAUGUST1. Valid to 9.7.2011

Posted in AIX.

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adding clients to existing VIO environment cont’d.,

The previous post ended at the place where we have recognized that we cannot add any more virtual adapters to the VIO server. The selected by us for the new virtual FC adapter slot number happen to equal to the value of the VIO server maximum number of virtual adapters. With HMC GUI, we modified the value on each VIO server (we have two in this managed “frame”) and after shutting it down, we powered it back using the “activate” the profile option. By the way, we changed the “maximum number of adapters” from 60 to 200.

Unfortunately, what has been described so far is not all. In this environment, VIO clients (partitions) receive their boot disks (the rootvg disks) from each VIO server which means that each time a VIO server goes down on disk from a client rootvg becomes missing and the rootvg becomes stale. This is true for all client partitions for this managed system.

Posted in AIX, Real life AIX, VIO.

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Delayed SEA Failover

Yesterday, while failing over a pair of VIO servers, we noticed that the usual two to three “ping” loss turned into a 40 second delay….. A few partitions with Oracle did not really liked it and crashed. Fortunately for us these were not the “Production” machines just the “Test” and “Development”.
After opening a PMR we speculated for a while about the fact that our “SEA” adapters have several vlan tags associated with and maybe this is the reason for the delay. Well, today we know more and do not need to speculate.
Please follow the link bellow which not only shows how to perform SEA failover and how to test it but also indicates that the presence of the “Spanning Tree Protocol” could be responsible for our experience – the long delay in network services for VIOS clients.

Here is the link: https://www-304.ibm.com/support/docview.wss?uid=isg3T1011063


Posted in AIX, Real life AIX.

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fsck all file systems of a volume group

Fujitsu America, Inc.

What always “works” did not work today. It is almost Friday, isn’t it? As the result file systems in the selected volume groups on all partitions in a managed system needs to be fsck’ed. There is a large number of partitions there so executing fsck manually quickly become boring…. . The few lines bellow can help if you have to do the same.
Just replace the vg_name with the appropriate volume group name and execute it as a script or directly from the command line.

lsvg -l vg_name | awk '{print $1, $7}' | while read lv fs
do
umount $fs
fsck -y /dev/$lv
mount $fs
done

You could insert fuser -kux $fs on the next line following the do. Occasionally, there could be a processes accessing a file in a file systems ($fs) preventing umount from doing its job. The command fuser -kux kills all processes associated with $fs allowing umount to do what is expected form it.

A day later:
I invite you to read the comment left by Mr. Anthony English. Especially the part about the nested file systems. For you who are “fresh” to UNIX (AIX) this could be an important bit of information.

Posted in AIX, Real life AIX.

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adding clients to existing VIO environment

The old saying say – “practice makes masters”. So accordingly, let’s walk again through the process of adding a new client (partition) to an existing environment controlled via two VIO servers.
Life being what it is, has a “small” surprise in store for us. Just keep reading and you will find out.

Posted in Real life AIX.


replacing (hot-swap) failed disk in rootvg

IBM called me because one of my hosts called them reporting a failed disk in rootvg. It was the hdisk0 that decided to quit. A few minutes later, a service engineer called my to let me know that he is driving with the new disk. I had about an hour to get ready. The following text describe the process of replacing a non-SAN disk in rootvg.

Posted in AIX, Real life AIX.

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Changing Volume Group Type and Missing File Systems

I am in my cube; it is 7 o’clock in the morning. My horoscope says that today I will have an interesting day. Really? Who cares? It is just a horoscope!
A few minutes later, I receive an email from our automated Work Order system. A users requests expansion of a particular file system. Well, if this is not a “routine” process then I do not know what a “routine” process is.

It did not take long to find out the volume group did not have the required 100GB of free capacity left. So, I reassigned the Work Order to our SAN team – “Please expand any of these hdisks (LUNs) by 100GB”. It was a matter of a few minutes and I had the Order back – my request has been processed.

The application was already “down”, the file systems “un-mounted” and I was ready to proceed with the “routine”.


Posted in Real life AIX.

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vi fails to open large files

Have you ever seen something similar:

# vi /some/path/to/a/large text/file
"/some/path/to/a/large text/file"ex: 0602-026 No more memory for the append. Too many lines in the file.
ex: 0602-101 Out of memory saving lines for undo.

and after you checked the /etc/security/limit and verified that /var/ and /tmp are not too full the file still could not be open for reading? Well, today, it happen here.

After googling for a while I came out with this post on one of IBM sites:

Posted in AIX, Real life AIX.

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Changing value of disk queue_depth parameter

It has been noted installing VIO clients with virtual disk adapters and MPIO that the disk’s original queue_depth values are small, too small indeed.

lsattr -El hdisk## | grep queue_depth
queue_depth    3       Queue DEPTH            True

As this quickly becomes an issue as the systems will “look” slow we have to respond changing the queues to a more reasonable value. If there are only a few disks the change is easy. But as the number of disks grows the amount of effort required to do the job grows too. Bellow, you will see how this change can be implemented across all disks except the ones that belong to the rootvg. By the way, for this change to be effective the volume groups containing these disks should be varried off which implies that their file systems will have to be un-mounted. So, with this two conditions satisfied, lets execute straight from the command line:

for pv in `lspv -v "hdisk0|hdisk1" | awk -F '{print $1}'`
>do
>chdev -l pv$ -P -a queue_depth=32
>done

The > character will by automatically added by the shell – do not enter this symbol! Now, vary on the volume groups, mount their file systems and proceed to the next task on your list.

To validate the change, type in:

for pv in `lspv -v "hdisk0|hdisk1" | awk -F '{print $1}'`
>do
>echo $pv
> lsattr -El $pv | grep queue
>done

Posted in Real life AIX.

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