unixadmin.free.fr Handy Unix Plumbing Tips and Tricks

Drive paths to library client taken offline when server option SANDISCOVERY set to ‘YES’

Technote (troubleshooting)

Problem(Abstract)

This message in the activity log of the library manager appears: ANR1772E The path from source to destination is taken offline.

Symptom

On the library client, these messages are observed in the activity log when a library sharing session is opened to the library manager:

On the library manager, you can see this corresponding message showing the path to the drive being taken offline:

Cause

The SAN discovery's query of the HBA has timed out, and the path is taken offline. This can occur in SAN environments with a large number of devices.
Diagnosing the problem

Verify that there is not an underlying hardware problem causing the drives paths to go offline.

Check the value of the SANDISCOVERYTIMEOUT option on the library clients and the library manager. The default value is 15 seconds:

Resolving the problem

If the value of the option is at or near the default value of 15 seconds, increase to a greater number. For example:

Why Are Tapes with PRIVATE Status Not Found in QUERY VOLUME Output?

Technote (FAQ)

Question

QUERY LIBVOLUME shows tape volumes with status of PRIVATE, but the same volumes do not show up with the command: Q VOL

Why are these tapes PRIVATE?

Answer

QUERY VOLUME will only return information about volumes that belong to stgpools, but there are other types of volumes that can have valid data on them: DB backups, exports, backupsets and remote volumes that belong to a Library Client server.

The volume history will keep a record of all volumes and you can display these other types of non-stgpool volumes with the following commands:

If a PRIVATE volume is not part of a stgpool and does not display in any of the above Q VOLH commands then you can set it to scratch using the command:

If you do have a library sharing environment it is recommended to run an AUDIT LIBRARY on the Library Client servers prior to changing the status of a volume to scratch on the Library Manager server.

Using ‘dd’ to verify Tivoli Storage Manager tape volume labels

Question
How can I use the Unix 'dd' command to verify a tape volume label?

Answer
The first step that may be necessary to verify a tape volume label is to find out the block size in use on that tape volume. This parameter is typically set on the physical tape library console interface and will vary between manufacturers so the ideal place to search is on the manufacturer website.
There is a method to manually find out the block size as follows:

On most Unix systems, the 'dd' command will output a message indicating a read failed from a tape drive (and corresponding tape volume) along with insufficient memory message. For example on AIX:

The 'if' parameter must reference a valid path to a drive that contains the volume you are seeking information about. This volume may be loaded using a utility such as tapeutil or directly from the physical library's console management. The drive should not be in use by Tivoli Storage Manager at the time the command is run and it is recommended to take the drive offline to Tivoli Storage Manager.

The 'ibs' parameter indicates the block size to use in bytes unless a 'k' is specific, in which case the parameter is read as kilobytes. A value of 32 bytes, as in the example above, is a good starting value. If this command returns a memory related error message then the value can be doubled.

The value specified for the block size is still smaller than what is actually on the volume so another error is generated. The value must be increased (each time doubling it) until no error message is reported:

Once the correct block size has been discovered, the 'dd' command should not generate a memory error when reading from the volume.
Now that the block size is known, the data on the first block of the tape can be dumped to a file:
dd bs= conv=ascii if= of=/tmp/.out

For example:

Once the file is file '/tmp/block1.out' is written, the file may be viewed in any text editor or the cat command can be used:

In this case the 'VOL1200312' is the label of the tape volume residing in the drive /dev/rmt1.

Source: IBM Technote

How to add a hardware error in AIX errlog

Comment générer des erreurs hardware dans l'errlog d'AIX. Utile pour tester des logiciels de supervision ou la gestion des évènements sous PowerHA.
Voir le fichier /usr/include/sys/errids.h pour les LABELS errpt.

Virtual HMC for November 2015

The IBM Power Systems Hardware Management Console (HMC) virtual appliance can be used to manage any of the systems that are supported by the version 8 HMC, which includes Power Systems servers with IBM POWER6, POWER7, and POWER8 processors.

The Power Systems HMC virtual appliance offers these benefits:

Provides hardware, service, and basic virtualization management for your Power Systems servers
Offers the same functionality as the traditional HMC
Runs as a virtual machine on an x86 server virtualized either by VMware ESXi or Red Hat KVM

Source: IBM

AIX Crash always on d_map_list_tce()

Problem

AIX 6100-04-05-1015 Crash always on d_map_list_tce() with with EMC Symmetrix FCP VRAID storage disk.

Local Fix
Stop the replication between storage and DR site

IBM APAR
Not yet tested with replication

IBM Spectrum Protect formerly Tivoli Storage Manager

Beginning with Version 7.1.3, IBM Tivoli Storage Manager is now IBM Spectrum Protect™.
Beginning with Version 4.1.3, IBM Tivoli Storage FlashCopy® Manager is now IBM Spectrum Protect™ Snapshot.

Product name cross reference

Source:  IBM Technote

Scheduled « Backup VM » processes more virtual machines than expected.

Technote (troubleshooting)