[Leaplist] Problems w/ users under CentOS 5.3 ....

[Bryan J Smith]

On Wed, 2009-09-02 at 17:50 -0500, William A. Mahaffey III wrote:
> Soooooo tacky to self-reply, but for posterity here goes: the problem 
> here turned out to be that we were trying to give user-process too much 
> stack space.  This caused the login shell to fail, eventually screwing 
> the rest of the graphical login up.

And this was because ... and here it comes ... (oh joy!) @-ppp

> We have had (for years) a custom initialization file in /etc/profile.d
> with a line in it that said:
> limit stackspace 512m
> this worked AOK under SuSE 9.3 32-bit (as did 1536m), but not under 
> CentOS 5.3 32-bit (we have 3 GB of RAM on the machine).

And what did I warn you about?  @-ppp (and big grin)

Exact words ...  

"Reality:  you switched to a Fedora-based system from a SuSE-based
system, and an older one at that.  Expect issues."

And most, most _specifically_ ...  

"Fedora and SuSE based systems have different profile/bash settings"

I could only assume your differences were in the user profiles, and not
system-wide, especially after you replied ...

"I *did* start from the pristine CentOS after the 1st barf"

Actually, you did not.  You didn't merely just reuse only your home
directories, you _modified_ the "prestine" CentOS root yourself.  Most
specifically, the /etc/profile.d.

Again, I warned you about that.  @-ppp

So instead of having only user profile differences of SuSE into a
Fedora-based system, you moved your system-wide differences of SuSE into
a Fedora-based system.  You copied over your /etc/profile.d from a SuSE
to a Fedora based system and assumed it would work.  It doesn't.  @-ppp

This is exactly what I predicted would happen, only I took your comments
that you only had legacy SuSE stuff in the user profiles at face value.
I guess my mistake for assuming you wouldn't touch that "prestine"
root. ;)

[ "Real Life":  Be forward on all that you change.  I get paid the "big
bucks" because I catch people when they don't.  Had I been the one that
installed CentOS, and then you modified it, then come back to me, I
would have caught this in 2 minutes.  Why?  Because I maintain
configuration management on this and would have caught it in a diff.
Again, my daily "real life" an why I get paid the "big bucks." ]

> When I commented that line out, the login went AOK, but we only have
> 10MB of stackspace.  I seem to recall something about a PAE kernel
> being needed under RedHat  to get a ~4 GB address space for user
> processes, so I will look into  that tomorrow.

You only get up to 3GiB per user process period using any 32-bit kernel.
No PAE kernel on 32-bit can overcome that limit at all.

Red Hat did offer a 4G/4G kernel model in Red Hat Enterprise Linux
Release 3 and 4 called "hugemem."  But that is no longer offered in Red
Hat Enterprise Linux Release 5, because Red Hat highly recommends
Linux/x86-64 for more than 4GiB of RAM, and reduced the official amount
supported to 16GiB on 32-bit (and that's with caveats).

Why do you need such a huge stack size again?



-- 
Bryan J  Smith         Professional, Technical Annoyance 
Linked Profile:       http://www.linkedin.com/in/bjsmith 
-------------------------------------------------------- 
Only engineers can solve the growing needs of consumers
Stop being "aware" (that's so '70s) and start supporting
real solutions that actually work and sustain the planet




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