To add a PVID to a disk, enter:

# chdev -l vpathxx -a pv=yes

# chpv -C vpathxx

To mount:

1. Build a logical volume (the size of an ISO image, better if a little bigger).
2. Create an entry in /etc/filesystem using that logical volume (LV), but setting its Virtual File System (V'S) to be cdrfs.
3. Create the mount point for this LV/ISO.
4. Copy the ISO image to the LV using dd.
5. Mount and work on it like a mounted CD-ROM.

/IsoCD:

dev = /dev/lv09
vfs = cdrfs
mount = false
options = ro
account = false

1. Unmount the file system.
2. Destroy the logical volume.

JFS2 filesystems allow you to create file system snapshots. Creating a snapshot is actually creating a new file system, with a copy of the metadata of the original file system (the snapped FS). The snapshot (like a photograph) remains unchanged, so it's possible to backup the snapshot, while the original data can be used (and changed!) by applications. When data on the original file system changes, while a snapshot exists, the original data is copied to the snapshot to keep the snapshot in a consistant state. For these changes, you'll need temporary space, thus you need to create a snapshot of a specific size to allow updates while the snapshot exists. Usually 10% is enough. Database file systems are usually not a very good subject for creating snapshots, because all database files change constantly when the database is active, causing a lot of copying of data from the original to the snapshot file system.

In order to have a snapshot you have to:

• Create and mount a JFS2 file system (source FS). You can find it in SMIT as "enhanced" file system.
• Create a snapshot of a size big enough to hold the changes of the source FS by issuing smitty crsnap. Once you have created this snapshot as a logical device or logical volume, there's a read-only copy of the data in source FS. You have to mount this device in order to work with this data.
• Mount your snapshot device by issuing smitty mntsnap. You have to provide a directory name over which AIX will mount the snapshot. Once mounted, this device will be read-only.

# snapshot -o snapfrom=$FILESYSTEM -o size=${SNAPSIZE}M

# snapshot -q $FILESYSTEM

# mkdir -p /snapshot$FILESYSTEM

# SNAPDEVICE=`snapshot -q $FILESYSTEM | grep -v ^Snapshots | grep -v ^Current | awk '{print $2}'`

# mount -v jfs2 -o snapshot $SNAPDEVICE /snapshot$FILESYSTEM

# unmount /snapshot$FILESYSTEM

# snapshot -d $SNAPDEVICE

# rm -rf /snapshot$FILESYSTEM

A very nice command to use when you either want to show someone remotely how to do something on AIX, or to allow a non-root user to have root access, is portmir.

First of all, you need 2 users logged into the system, you and someone else. Ask the other person to run the tty command in his/her telnet session and to tell you the result. For example:

user$ tty
/dev/pts/1

root# portmir -t /dev/pts/1

# portmir -o

IBM License Use Management (LUM) is the IBM product for technical software license management deployed by most IBM use-based priced software products, such as the C Compiler.

More info on:
License Use Management
License Use Management - Library

If you wish to put AIX files on a CD, you *COULD* use Windows. But, Windows files have certain restrictions on file length and permissions. Also, Windows can't handle files that begin with a dot, like ".toc", which is a very important file if you wish to burn installable filesets on a CD.

How do you solve this problem?

• Put all files you wish to store on a CD in a separate directory, like: /tmp/cd
• Create an ISO file of this directory. You'll need mkisofs to accomplish this. This is part of the AIX Toolbox for Linux. You can find it in /opt/freeware/bin.

  # mkisofs -o /path/to/file.iso -r /tmp/cd

• This will create a file called file.iso. Make sure you have enough storage space.
• Transfer this file to a PC with a CD-writer in it.
• Burn this ISO file to CD using Easy CD Creator or Nero.
• The CD will be usable in any AIX CD-ROM drive.

To create a printer queue that dumps it contents to /dev/null:

# /usr/lib/lpd/pio/etc/piomkpq -A 'file' -p 'generic' -d '/dev/null' -D asc -q 'qnull'

# lpr -Pqfile /etc/motd

Let's say you wish to calculate with dates within a Korn Shell script, for example "current date minus 7 days". How do you do it? There's a tiny C program that can do this for you, called ctimed. You can download it here: ctimed.tar.

Executable ctimed uses the UNIX Epoch time to calculate. UNIX counts the number of seconds passed since Januari 1, 1970, 00:00.

So, how many seconds have passed since 1970?

# current=`./ctimed now`

# let week=7*24*60*60

# ./ctimed $aweekago

A very usefull command to list microcodes is lsmcode:

# lsmcode -c

An AIX system should have a single default gateway defined. However, sometimes, it does occur that a system has multiple default gateways. Here's information to detect multiple default gateways and how to get rid of them:

First, obtain how many gateways there are:

# odmget -q "attribute=route" CuAt

CuAt:
        name = "inet0"
        attribute = "route"
        value = "net,-hopcount,0,,0,192.168.0.1"
        type = "R"
        generic = "DU"
        rep = "s"
        nls_index = 0

CuAt:
        name = "inet0"
        attribute = "route"
        value = "net,-hopcount,0,,0,192.168.0.2"
        type = "R"
        generic = "DU"
        rep = "s"
        nls_index = 0

# chdev -l inet0 -a delroute="net,-hopcount,0,,0,192.168.0.2"
Method error (/usr/lib/methods/chginet):
        0514-068 Cause not known.
0821-279 writing to routing socket: The process does not exist.
route: not in table or multiple matches
0821-207 chginet: Cannot add route record to CuAt.

# odmget -q "attribute=route" CuAt

CuAt:
        name = "inet0"
        attribute = "route"
        value = "net,-hopcount,0,,0,192.168.0.1"
        type = "R"
        generic = "DU"
        rep = "s"
        nls_index = 0