🚀 go-pugleaf

In article <2854@stpstn.UUCP> aad@stepstone.com writes:
>I've found that our AIX machines have the annoying tendency to get
>corrupted, giving an "error reading iodn 16384" (or some number close to
>that) when trying to boot, and nothing short of re-installing seems to
>solve it. 

iodn 16384 is your root filesystem.  An I/O error on the root
filesystem would tend to keep your system from starting, certainly an
annoying thing.  Once VRM and root have come up, hard errors on
filesystems will usually cause FSCK failures.  The usual procedure for
dealing with this would be to make a backup of your root filesystem at
some point, and to attempt to restore it using the stand-alone
install/maint diskette, when the failure occurred. The install/maint
diskette is in the install diskette set.  You can also run fsck from
that diskette, start the stand-alone shell, and mount /dev/hd0 onto
/mnt, and chroot to /mnt or just cd there and try to figure out what
is wrong.

I've been running AIX on a number of machines for a fair while now.
This doesn't happen to me on any of the recent disk drives, although
there was a 70 meg drive that customers never saw....but anyway, I'd
seriously consider running hardware diagnostics, and looking for
failing parts or disk drives.  I'd also consider talking to the
hardware folks about trying to swap parts.  If it is happening on more
than one machine, well, I dunno.  I'd still run diagnostics, but I'd
also call defect support.  New fix levels are cut frequently.

> AIX also has really poor default partitioning.  Doing a
>default install on an RT with 3 114 meg drives results in a total of
>about 70 or 80 meg used, across the drives.

It should be noted that you can change this during install, and that
you can change it after install by backing up that "minidisk",
deleting it using the install maint disk and adding it with the same
iodn, and restoring the backup.  But it probably will be painful for
the first time user who does not yet know their requirements, and who
does not fit the defaults.  Unfortunately, defaults for something as
complex as space utilization by filesystem are difficult to choose
such that they fit most users.  Indeed, we are struggling with this
problem for Watson Research's "standard" configuration, and we have
come to believe that there is no set of standard defaults that will
satisfy anyone.  Some are less painful than others.

>A default of 16 maximum
>ptys is also bad, as is having to create them one at a time.

Well, as you probably know, the X-Windows manual describes how to
increase the number of pty's.  This involves parameter changes in
/etc/master and a kernel make.  Some people in IBM run the devices
command under 'tee', create a set of pty's, and then pipe that file to
devices whenever they need to create pty's after that.  I wrote a Q&D
program to do it.

The problem with increasing the number of pty devices by default, far
as I know, is that each pty ties up system resources.  Also,
configuring 64 pty devices makes boot, an already painfully long
process, take a lot longer.  I know. cause I run with 64 pty's.

>I find it
>amazing that online manual pages are a seperate product, and the
>elements from IBM's mainframe os's like "minidisks" instead of partitions
>and ocurrences of "IPL" are kind of odd.

(no comment) 

>>Having seen AIX go from 2.1 to 2.2.1 I have experienced the "painless"
>>upgrades (compared to what I've heard about some BSD boxes :-) except
>>that installing from floppy is ridiculous.
>
>IBM installed 2.1.2 on our RT's, with default partitioning.  We thought
>we just had one 70 meg drive in there until I opened the suckers up and
>found 3 114's. 

Did you never run the minidisks command?  It will tell you how many
physical drives you have, how the logical "minidisks" are laid out on
those physical drives, and will allow you to allocate more logical
"minidisks". (Using "user-friendly" dialogs and full screen menus...)

>I just installed 2.2 from scratch, and it went fairly well
>after I figured out which of the subsets I needed.  I haven't tried an
>actual incremental upgrade, but many, many vendors do a less than admirable
>job at them.  I was once told that 2.2.1 would do NFS -- is true?  Is it
>a seperate product?

Our usual tack is to install all of everything.  2.2.1 will support
the NFS product, which as far as I know, is separate.  


-- 
Nick Simicich --- uunet!bywater!scifi!njs --- njs@ibm.com (Internet)