If you run:

# powermt display dev=all

# powermt restore

# powermt reset
# powermt config

# powermt check

From powerlink.emc.com:

1. Before making any changes, collect host logs to document the current configuration. At a minimum, save the following: inq, lsdev -Cc disk, lsdev -Cc adapter, lspv, and lsvg
2. Shutdown the application(s), unmount the file system(s), and varyoff all volume groups except for rootvg. Do not export the volume groups.

   # varyoffvg <vg_name>

   Check with lsvg -o (confirm that only rootvg is varied on)
   If no PowerPath, skip all steps with power names.
3. For CLARiiON configuration, if Navisphere Agent is running, stop it:

   # /etc/rc.agent stop

4. Remove paths from Powerpath configuration:

   # powermt remove hba=all

5. Delete all hdiskpower devices:

   # lsdev -Cc disk -Fname | grep power | xargs -n1 rmdev -dl

6. Remove the PowerPath driver instance:

   # rmdev -dl powerpath0

7. Delete all hdisk devices:
   For Symmetrix devices, use this command:

   # lsdev -CtSYMM* -Fname | xargs -n1 rmdev -dl

   For CLARiiON devices, use this command:

   # lsdev -CtCLAR* -Fname | xargs -n1 rmdev -dl

8. Confirm with lsdev -Cc disk that there are no EMC hdisks or hdiskpowers.
9. Remove all Fiber driver instances:

   # rmdev -Rdl fscsiX

   (X being driver instance number, i.e. 0,1,2, etc.)
10. Verify through lsdev -Cc driver that there are no more fiber driver instances (fscsi).
11. Change the adapter instances in Defined state

    # rmdev -l fcsX

    (X being adapter instance number, i.e. 0,1,2, etc.)
12. Create the hdisk entries for all EMC devices:

    # emc_cfgmgr

    or

    # cfgmgr -vl fcsx

    (x being each adapter instance which was rebuilt). Skip this part if no PowerPath.
13. Configure all EMC devices into PowerPath:

    # powermt config

14. Check the system to see if it now displays correctly:

    # powermt display
    # powermt display dev=all
    # lsdev -Cc disk
    # /etc/rc.agent start

An easy way to see the status of your SAN devices is by using the following command:

# powermt display
Symmetrix logical device count=6
CLARiiON logical device count=0
Hitachi logical device count=0
Invista logical device count=0
HP xp logical device count=0
Ess logical device count=0
HP HSx logical device count=0
==============================================================
- Host Bus Adapters -  --- I/O Paths ----  ------ Stats ------
### HW Path            Summary Total Dead  IO/Sec Q-IOs Errors
==============================================================
  0 fscsi0             optimal     6    0       -     0      0
  1 fscsi1             optimal     6    0       -     0      0

# powermt display dev=all

It will sometimes occur that a file system reports storage to be in use, while you're unable to find which file exactly is using that storage. This may occur when a process has used disk storage, and is still holding on to it, without the file actually being there anymore for whatever reason.

A good way to resolve such an issue, is to reboot the server. This way, you'll be sure the process is killed, and the disk storage space is released. However, if you don't want to use such drastic measures, here's a little script that may help you trying to find the process that may be responsible for an inode without a filename. Make sure you have lsof installed on your server.

#!/usr/bin/ksh

# Make sure to enter a file system to scan
# as the first attribute to this script.
FILESYSTEM=$1
LSOF=/usr/sbin/lsof

# A for loop to get a list of all open inodes
# in the filesystem using lsof.
for i in `$LSOF -Fi $FILESYSTEM | grep ^i | sed s/i//g` ; do
# Use find to list associated inode filenames.
if [ `find $FILESYSTEM -inum $i` ] ; then
echo > /dev/null
else
# If filename cannot be found,
# then it is a suspect and check lsof output for this inode.
echo Inode $i does not have an associated filename:
$LSOF $FILESYSTEM | grep -e $i -e COMMAND
fi
done

Everybody is usually quite familiar with how to open an X11 windows GUI on a Windows PC. It involves running an X-server on the PC, for example Xming. Install this with all default settings. Make sure you have PuTTY installed on your PC before installing Xming. Then on your PC run Xlaunch, and make sure to set your DISPLAY to a higher value, for example "10" and to check "No Access Control".

Log in to the UNIX host through PuTTY, and before starting the session to your UNIX host, go to "Connection" -> "SSH" -> "X11" in PuTTY and select "Enable X11 forwarding", and then click "Open". Once logged in, set the DISPLAY variable to the IP address of your PC and set the correct display, for example:

# export DISPLAY="154.18.20.31:10"

# xeyes

# ssh -X -Y -C otherunixhost

With POWER6, the default addresses of the service processors have changed. This only applies to environments where the managed system was powered on before the HMC was configured to act as an DHCP server. The Service Processors may get their IP-Addresses by three different mechanisms:

1. Addresses received from a DHCP Server.
2. Fixed addresses given to the interfaces using the ASMI.
3. Default addresses if neither of the possibilities above is used.

Port HMC1: 192.168.2.147/24
Port HMC2: 192.168.3.147/24

First Service Processor:
Port HMC1: 169.254.2.147/24
Port HMC2: 169.254.3.147/24

Second Service Processor:
Port HMC1: 169.254.2.146/24
Port HMC2: 169.254.3.146/24

If you decide to update to HMC release 7.3.5, Fix Central only supplies you the ISO images.

This procedure describes how you can update your HMC using the network without having to sit physically in front of the console.

First, check if this new HMC level is supported by the firmware levels of your supported systems using this link. If you're certain you can upgrade to V7.3.5, then make sure to download all the required mandatory fixes from IBM Fix Central. Don't download the actual base level of HMC v7.3.5 of 3 Gigabytes. We'll download that directly to the HMC later on.

Then, perform the "Save upgrade data" task using either the Web interface or the command line. Then get the required files from the IBM server using ftp protocol using the following command:

# getupgfiles -h ftp.software.ibm.com -u anonymous --passwd ftp
-d /software/server/hmc/network/v7350

# chhmc -c altdiskboot -s enable --mode upgrade

# hmcshutdown -r -t now

If your HMC is located behind a firewall and your only access is through SSH, then you have to use SSH tunneling to get browser-based access to your HMC. The ports you need to use for setting up the SSH tunnel are: 22, 23, 8443, 9960, 9735, 657, 443, 2300, 2301, 2302 and 12443. This applies to version 7 and up of the HMC. For example, if you're using a jump server to get access to the HMC, you need to run:

# ssh -l user -g -L 12443:10.48.32.99:12443 -L 8443:10.48.32.99:8443 -L 9960:10.48.32.99:9960 -L 9735:10.48.32.99:9735 -L 2300:10.48.32.99:2300 -L 2301:10.48.32.99:2301 -L 443:10.48.32.99:443 -L 2302:10.48.32.99:2302 -L 657:10.48.32.99:657 -L 22:10.48.32.99:22 -L 23:10.48.32.99:23 jumpserver.domain.com -N

Linux allows binding multiple network interfaces into a single channel/NIC using special kernel module called bonding. According to official bonding documentation, The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical "bonded" interface. The behavior of the bonded interfaces depends upon the mode; generally speaking, modes provide either hot standby or load balancing services. Additionally, link integrity monitoring may be performed.

Setting up bounding is easy with RHEL v4.0. Red Hat Linux stores network configuration in /etc/sysconfig/network-scripts/ directory. First, you need to create bond0 config file:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0

DEVICE=bond0
IPADDR=192.168.1.20
NETWORK=192.168.1.0
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

alias bond0 bonding
options bond0 mode=1 miimon=100

# modprobe bonding

# service network restart

# less /proc/net/bonding/bond0
Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:59

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:63

Check the relation between vpaths and hdisks:

# lsvpcfg

# datapath query adapter

# lsvg -o | lsvg -i | grep -i stale