paul.deluca – Page 21 – Eclipse Systems Knowledge Base

How do I increase the size of my AIX dump device?

If you are receiving the following error in your AIX errpt, you need to increase the size of your dump device:

IDENTIFIER TIMESTAMP  T C RESOURCE_NAME  DESCRIPTION
E87EF1BE   0925150011 P O dumpcheck      The largest dump device is too small.

First, identify the largest dump device using the “/usr/lib/ras/dumpcheck -p” command, as in the following example:

eclipse:root:/# /usr/lib/ras/dumpcheck -p
The largest dump device is too small.

Largest dump device
         lg_dumplv
Largest dump device size in kb
         1048576
Current estimated dump size in kb
         1501593

In this example, the “dump device” that needs to be increased is “lg_dumplv”. If a file system needs to be increased, the output will give a “file system name”.

If a logical volume needs to be increased, review the current size of this logical volume using the lslv command, similar to the following example:

eclipse:root:/# lslv lg_dumplv
LOGICAL VOLUME:     lg_dumplv              VOLUME GROUP:   rootvg
LV IDENTIFIER:      0001c02b0000d60000000114a8a42e67.11 PERMISSION:     read/write
VG STATE:           active/complete        LV STATE:       opened/syncd
TYPE:               sysdump                WRITE VERIFY:   off
MAX LPs:            512                    PP SIZE:        128 megabyte(s)
COPIES:             1                      SCHED POLICY:   parallel
LPs:                8                      PPs:            8
STALE PPs:          0                      BB POLICY:      relocatable
INTER-POLICY:       minimum                RELOCATABLE:    yes
INTRA-POLICY:       middle                 UPPER BOUND:    32
MOUNT POINT:        N/A                    LABEL:          None
MIRROR WRITE CONSISTENCY: on/ACTIVE
EACH LP COPY ON A SEPARATE PV ?: yes
Serialize IO ?:     NO

Note the number of LPs, and increase the logical volume by a reasonable extent. In this example, I can double the size of the logical volume by adding an additional 8 LPs, as shown in the example command below:

eclipse:root:/# extendlv lg_dumplv 8

If a file system needs to be increased, review the current and estimated sizes of the file system provided by the dumpcheck utility. Then, expand the filesystem using a command similar to the following example:

chfs -a size=8G /var/adm/ras

Once you have confirmed the new size same lslv or df commands, run the same dumpcheck command to verify that no errors or warnings are generated. If the situation has been resolved, running the dumpcheck command will simply return you to the command prompt with no errors.

For more information on the AIX dump device, it’s purpose, and more detailed troubleshooting steps, see IBM’s website: Increase the Size of a Dump Device

How do I launch a root shell from within Eterm?

It is sometimes useful to spawn a UNIX shell from within an Eterm session. Here is the procedure:

From within your active Eclipse session in Eterm
Press F2
Press T to launch the TCL shell
Type the following to launch a UNIX shell:
```
sh
```
Type the following to escalate the shell to superuser (root) mode:
```
su -
```
Enter the root user’s password when prompted
You are now at the root (#) prompt
To exit, type:
```
exit
exit
```
Press ESC at the TCL (;) prompt

Note: the user logged into Eclipse must have access to TCL, and you must know the root password.

For further reference, view a screencast of this procedure.

How do I fix a blank VNC session?

If you find yourself facing a blank VNC session, try restarting the VNC service. Log in to the server as root and run:

service vncserver restart

After the service has restarted, you should be able to return to a fully-functional VNC session.

This behavior typically results from a VNC user accidentally logging out of the GNOME desktop interface instead of simply disconnecting the VNC session.

Where can I find training resources for Linux?

The Internet is a veritable treasure trove of Linux educational resources, but here are a few that we’ve hand-picked as especially useful.

Google

First, Google it. Linux is so widely deployed that most common administration issues have been encountered, resolved and written about by others.

Manuals

Red Hat provides a bunch of useful manuals on their public RHEL documentation site. While a bit out-dated, the Introduction to System Administration is an especially good guide.

Blogs

There are many Linux “howto” blogs on the Internet that cover common (and not so common) administration tasks. One of the better blogs is nixCraft (aka cyberciti.biz).

Books

While there are a myriad of books available on RHEL administration, one of the most comprehensive is Michael Jang’s “RHCSA/RHCE Red Hat Linux Certification Study Guide”. While targeted towards certification-seekers, this tome covers just about everything you’ll need to know about Linux administration in a single, inexpensive volume.

Computer-Based Training

For those who learn better visually, Michael Jang has also put together a virtual CBT course covering RHEL administration topics. Each section is presented with both narrated slides and screencasts of demos. While it’s more expensive than the book, it’s also far less expensive than an instructor-led course.

Instructor-Led Training

Red Hat and other 3rd party vendors offer instructor-led training both on-site and via virtual labs. While comparatively expensive, you are offered opportunities to collaborate one-on-one with expert instructors and test out your newfound knowledge in a safe, lab environment.

Eclipse-Specific Administration Training

For Eclipse-specific administration, please refer to the knowledge base or contact our Education team to see if there are any new instructor-led or computer-based training courses available.

How do I limit the size of CUPS log files?

To reduce the size of the CUPS logs:

Back up the existing configuration settings:

cp /etc/cups/cupsd.conf /etc/cups/cupsd.conf.`date +%Y%m%d.%H%M%S`

Open the /etc/cups/cupsd.conf configuration file in your favorite editor (i.e. vim, nano, Gnome editor, etc.).

Locate the MaxLogSize setting, and change it to a smaller value. For example, 100 MB:

MaxLogSize 100m

Restart the CUPS print service to apply the changes:

service cups restart