How to scan and detect new luns in Linux (Veritas and EMC)

When new luns are become available for the server they are not being picked up automatically.
Simplest way - reboot the box.
More elegant way - scan for new luns and add them to existing configuration online.

On most of the distributions you may find rescan-scsi-bus.sh script which is responsible for triggering rescan.

Next - verify the current config - check how many luns are currently configured:
# powermt display
Symmetrix logical device count=121
CLARiiON logical device count=0
HP xp logical device count=0
Ess logical device count=0
Invista logical device count=0
=====================================================================
---- Host Bus Adapters ---- ---- I/O Paths -----  ------ Stats -----
###  HW Path               Summary   Total   Dead  IO/Sec Q-IOs Errors
=====================================================================
   2 lpfc                  optimal     242      0       -     0      0

   3 lpfc                  optimal     242      0       -     1      0

For more detailed output you may run:

# powermt display dev=all

To detect new luns and add them to the configuration run:

# powermt config

# powermt save

# powermt display

You should now see a more luns in the output.

Additionally if you're using Veritas Storage Foundation you may scan for new disk devices by triggering:

# vxdisk scandisks new

New devices will be visible and in "error" state (you will need to initialize them later):

# vxdisk -o alldgs list

DEVICE       TYPE            DISK         GROUP        STATUS

cciss/c0d0   auto:none       -            -            online invalid

emcpowera   auto:cdsdisk    -            (datadg)  online

emcpowerb    auto:cdsdisk    -            (datadg)  online

emcpowerc   auto:cdsdisk    -            (datadg)  online

emcpowerd   auto:cdsdisk    -            (datadg)  online

emcpowere   auto:cdsdisk    -            (datadg)  online

emcpowerf   auto            -            -            error

emcpowerg   auto            -            -            error

emcpowerh   auto            -            -            error

emcpoweri   auto            -            -            error

How to rename VCS resource or service group name

Recently I had to rename some service groups in my Veritas Cluster without restarting services running under its control.
I was little nervous because there was a huge database import ongoing I couldn't interrupt it.
Both hagrp and hares commands do not have built-in functionality to rename group/resource.
However there is an easy way of changing names without having cluster resources impacted.

First you need to stop the cluster using:
hastop -all -force
Important part is the "-force" option which allows cluster-controlled resources to stay online.
Now you can modify /etc/VRTSvcs/conf/config/main.cf file and change the name of group/resource.
Make sure it's changed everywhere (so if you have some dependencies or huge main.cf file it's best to search for every occurance of the original group/resource name).

Check if the modified config is still valid:
hacf -verify /etc/VRTSvcs/conf/config

If it's fine distribute new main.cf file to the other cluster nodes and start up cluster:
hastart

Finally verify if the new names are visible under running cluster:
hastatus -summary