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Minimum Filesystem Sizes

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mbucking

IS-IT--Management
Apr 8, 2003
1
NL
Hi there,
I need to write some acceptance criteria for AIX machines.
Now I need to know what the minimum filesystem sizes are that would be recommended. So not the default sizes as that will work for about 10 minutes......
Thanks a lot,
Maz
 
AIX upon installation (new installation) creates the rootvg filesystems as small as it can. Off the top of my head, I don't recall what those sizes are, but I'm pretty sure it fits into 2G or so, probably less.

AIX, also in its default configuration (aside from one little issue with the dpid2 daemon) will also run indefinately on that space, so I'm not certain what you mean by 10 minutes.
 
It depends on what you are using the system for. When you install the system, the size that AIX makes the filesystems may be too small for your purposes. I always make the sizes larger than the default.

Here are the sizes of my default filesystems on a system that is running several Oracle databases:
/: 131 MB
/usr: started out at about 1 GB, but AIX automatically extends the size if necessary when you use installp to add software.
/var 98 MB
/tmp 327 MB (Oracle requires a lot of space in /tmp when you install the application)
/home 425 MB (sort of large for /home, but there are a lot of developers on the system)
Paging started out at 2 GB.
 
hi,

It also depends on what applications you are running , whether you do a lot of printing becuase some applications require a temp area to write to when runnning certain jobs
normally /tmp , you need to find out how big this needs to be and set it accordingly , /var for printing depends if you have alot of printers or only a few . / can be left the same , you shouldn't really put alot of stuff in root
/home again depends on how many users you have and how much data they will keep in their home dirs.

HTH
 

On almost all systems the default size will work.

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support
 
Morsing, I have to disagree. For example, the default size for /tmp, for example, will make an installation of Oracle fail -- it's too small. The default for paging for one of my systems (2 GB) turned out to be 1/4 the size we eventually needed it to be. The default for /home may be OK for a production system, but it is most likely too small for a development system.

mbucking asked for suggestions on filesystem sizes that would last "longer than 10 minutes" -- and that's a smart way to plan an OS installation. Why cram the OS and the default filesystems into 2 or 3 GB on disks that are 18 GB or larger when, with a little bit of planning, you can lay out the filesystems on the disks pretty much from the beginning?

That is not to say you will never have to enlarge the filesystems, but planning the sizes with an eye to how the system is going to be used is more efficient.
 
Well, without any idea of what the goal is, no proper recommendations as to what to change from the start can be made. In and of itself, a default AIX install will run indefinately (again barring dpid2.log). Tell us what's going to run on it, and we can make better suggestions as to how to change the defaults.

For me, yes I usually bump up the size of /tmp, and the default paging space. I wouldn't do that if it was not called for.

I'm not sure what you mean by cramming 2-3G onto an 18G disk. Granted there's plenty of space to expand them if necessary, but in my own work, I prefer not to expand just because I can.

The only real issue, at least to me, is /home, and I've been known to move that into a data vg if it's going to end up containing data.
 
bi

The Oracle installation relies on the variable temp_dir (if I rememmber correctly) which can be set to any karge filesystem you wish to use, it is not manadatory to use /tmp :)

Alex
 
You can't choose the minimun file system sizes when installing, then it's a no-brainer. You can install AIX 4.3.3 on 450MB and 5x on 650MB without problems.


I hope it works...
Unix was made by and for smart people.
 
But would you really want to turn over a system to either production or development with the minimum, out of the box filesystem sizes?

The original question was what were recommendations for acceptance criteria for filesystem sizes for an AIX system -- and not the default sizes because mbucking knew the defaults wouldn't be large enough.

The brainer part is determining what the system is going to be used for and sizing the filesystems accordingly.
 
this is where vendor recommendations (for example, Oracle install guide) comes in handy. some idea of the intended use is a good idea, otherwise you spend your days doing "chfs -a size=+..." personally i feel it is good to allocate only what is minimally needed, with a bit extra for error, core files, etc.

IBM Certified -- AIX 4.3 Obfuscation
 
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