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Maximo 7.6 on AIX - Let's talk about sizing your file system.

Technical Blog Post


Maximo 7.6 on AIX - Let's talk about sizing your file system.


As many of you are aware Maximo 7.6 has hit the shelves, you may be already testing the installation and product. But what some may not know, is that the Maximo 7.6 Administrative workstation is now supported on other platforms then Windows. Yes, Maximo 7.6 and it's admin components can all be installed on Unix based operating systems, specifically Red Hat 6 and 7, Suse 11 and AIX 7.1. You can check out the Platform Matrix for more information on this (Click the Administrative Workstation Support tab).   As a configuration specialist, I enjoy a challenge, why take the easy route, when you can unlock the power of something new that may be a little bit more difficult, at the same time you will likely learn something and expand your knowledge into other areas.  We don't want to limit ourselves when it comes to knowledge sharing, so I'm going to start blogging a bit more on Unix based platforms such as Linux and AIX.  In this blog we will be tackling file sizing with SMIT (System Management Interface Tool),


Using smitty to change your file systems.


When dealing with AIX, your file systems may not be configured for the amount of space required by Maximo and it's middleware components. You might be thinking, well I have 200GB of disk space! why do I need to change anything? The importance is where that 200GB is allocated, for the most part it's likely not allocated at all.


Before allocating our disk space to the file systems, we need to determine how much we need. To do that you can head on over to the Maximo 7.6 System Requirements Wiki. From the Wiki click on the 'File Systems' link to see how much space is required.  You will have to do some addition here ( this won't be the last of the math in this blog), by looking at the chart, we will need to roughly ensure the following amount of space is allocated to appropriate file systems.


File System Space Required (MB)
/opt 2208
/usr 3994



I got this spacing information by adding up the required space from the installed components from the chart.  We have to keep in mind to add more space to the file system you will be copying the install to and extracting to. Also on the Wiki it doesn't show the spacing requirements for the admin workstation itself on Unix platforms, but this will install to opt, so allocate 7 - 10GB for that as well.  Looking at this chart we see 4 GB required in /usr (for the WebSphere) components. You will likely want\need to add more as this is an exact number.  For the purpose of this blog, I will add 10GB to the /usr file system.


It's important to note when working with the AIX file system and smitty, when adding space you are going to do it in blocks, rather then megabytes or gigabytes. The next question on your mind, is likely how do we convert gigabytes to blocks. To start I will note a block is a 512  byte unit. So when we want to add 10GB, we can times that 1024 to get the MB value of(10240) then times it again to get the kilobyte value (10485760) , then again to get the byte value ( 10737418240). Then we want to dived the byte value by 512 to get the block conversion. So 20971520 blocks is 10GB of space.


10x1024x1024x1024/512 = 20971520 blocks.


Again if you want to allocate 20GB of space the formula would be.


20x1024x1024x1024/512 = 41943040 blocks


Going down to megabytes, we would remove one of the multipliers, for example 500MB would be.

500x1024x1024/512 = 1024000


Alternatively you could do a quick search for block conversions and there will be a handful of online web tools to do this for you and likely give you more accurate numbers then the above. But do you really want to take the easy route? When it comes to math, go ahead!


Now that were all math wizards,  how do we add these 20971520 blocks to the /usr file system.  We will do this with smitty command which involves the  SMIT (System Management Interface Tool). Once you run smitty in your terminal the following options will appear. 




We want to modify our logical storage so click on System Storage Management (Physical & Logical Storage), then choose 'File Systems' on the next page that displays.  Then choose 'Add / Change /Show / Delete File Systems'.


Next we want to choose 'Enhanced Journaled File System' (J2FS), this differs from the 'Journaled File System' (JFS) as it has the ability to store larger files and provides 64 bit functionality. JFS is the recommended File System for 32 bit environments.  On the next page choose ' Change / Show Characteristics of an Enhanced Journaled File System' You will now see your current file systems, we want to choose /usr as seen below.





Once you click on /usr you will be brought to a page showing all the information on this file system.  We can see our block size we used for conversation earlier of 512 bytes and the current number of units, 4456448. So if we do the math backwards (divide by 1024 twice and multiply by 512) we can see that is roughly 2GB.





Now we want to add our blocks, as calculated earlier 10GB is roughly 20971520 blocks. Move down the list until you get to number of units and hit F7 to edit the value, enter in your block value for 10GB and hit enter again to commit your changes as seen in the next screen shot.



Were done! we can confirm our space was added by running the df -P.  In the chart you can see our allocated blocks, how much is used and how much is available. 




Now you will want to continue doing this for the other file systems that need to be extended. Next up (Likely next week) we will tackle extending the Paging Space required for DB2 and calculating the PP ( Physical Partitions) that need to be allocated.  I hope this was useful for anyone looking into AIX, whether it be for an actual implementation or just learning on a new platform.  As always, questions comments or criticisms, please post below.



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