POWER PATH

EMC PowerPath Commands

If your server has two HBA cards connected to EMC SAN storage device, you can implement
load-balancing, and fail-over on the HBA cards using the EMC PowerPath software.
Powermt management utility helps you manage I/O paths from the server to the EMC
storage device. In this article, let us discuss how to use powermt command with practical
examples.

1. powermt display Display High Level HBA I/O Paths

powermt display command (without any arguments), displays the available HBAs and their
current status.
The following examples, shows that there are 2 HBAs connected to the server, both the
HBAs are in active condition with 2 I/O paths each. qla2xxx indicates that it is using the QLogic HBA card.
This also indicates that the connected EMC device is CLARiiON, as it displays a value for
CLARiiON logical device count as 1.
# powermt display
Symmetrix logical device count=0
CLARiiON logical device count=1
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
==============================================================================
1 qla2xxx
optimal
2
0
0
0
2 qla2xxx
optimal
2
0
0
0

2. powermt display dev=all Display All Attached LUNs

This is the most frequently used powermt command, which will display all the attached
logical devices to the server.
# powermt display dev=all
Pseudo name=emcpowera
CLARiiON ID=AAA00000000000 [dev-server]
Logical device ID=1111111111111111111 [LUN 1]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP B, current=SP B
Array failover mode: 1
==============================================================================

---------------- Host --------------- Stor -- I/O Path - -- Stats --### HW Path

I/O Paths
Interf.
Mode
State Q-IOs Errors
==============================================================================
1 qla2xxx
sdd
SP A4
active alive
0
0
1 qla2xxx
sde
SP B4
active alive
0
0
2 qla2xxx
sdf
SP A5
active alive
0
0
2 qla2xxx
sdg
SP B5
active alive
0
0
Pseudo name=emcpowerb
CLARiiON ID=AAA00000000000 [dev-server]
Logical device ID=2111111111111111111 [LUN 2]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP A, current=SP A
Array failover mode: 1
==============================================================================
---------------- Host --------------- Stor -- I/O Path - -- Stats --### HW Path
I/O Paths
Interf.
Mode
State Q-IOs Errors
==============================================================================
1 qla2xxx
sdh
SP A4
active alive
0
0
1 qla2xxx
sdi
SP B4
active alive
0
0
2 qla2xxx
sdj
SP A5
active alive
0
0
2 qla2xxx
sdk
SP B5
active alive
0
0
The above indicates that there are two LUNs attached to the dev-server with 4 I/O paths
from the server to the SAN storage device.
The above command output indicates the following:
Pseudo name=emcpowera The device name that can be used by the server. For
example, /dev/emcpowera.
CLARiiON ID=AAA00000000000 [dev-server] - EMC CLARiiON CX3 serial number and
the server name.
Logical device ID=11111111 [LUN 1] LUN number. For example, LUN 1.
state=alive; policy=CLAROpt; This displays that this particular LUN is valid and using
the CLAROpt policy.
Owner: default=SP B, current=SP B This indicates that the default (and current)
owner for this LUN is storage processor SP B.

3. powermt display dev=emcpowera Display specific LUN

When there are multiple LUNs connected to a server, you might want to view information
about a specific LUN by providing the logical name of the LUN as shown below.
# powermt display dev=emcpowera
Pseudo name=emcpowera
CLARiiON ID=AAA00000000000 [dev-server]
Logical device ID=1111111111111111111 [LUN 1]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP B, current=SP B
Array failover mode: 1
==============================================================================
---------------- Host --------------- Stor -- I/O Path - -- Stats --### HW Path
I/O Paths
Interf.
Mode
State Q-IOs Errors
==============================================================================
1 qla2xxx
sdd
SP A4
active alive
0
0
1 qla2xxx
sde
SP B4
active alive
0
0
2 qla2xxx
sdf
SP A5
active alive
0
0
2 qla2xxx
sdg
SP B5
active alive
0
0

If the device is not available, youll get a Bad dev value as shown below.
# powermt display dev=emcpowerc
Bad dev value emcpowerc, or not under Powerpath control.

4. powermt check_registration Display PowerPath

Registration Key / Status
If youve lost the PowerPath registration key that youve used during the EMC PowerPath
installation, you can retrieve it using the following command.
# powermt check_registration
Key AAAA-BBBB-CCCC-DDDD-EEEE-FFFF
Product: PowerPath
Capabilities: All

5. powermt display options Display EMC PowerPath

Options
Displays the high level EMC SAN array options as shown below.
# powermt display options
Default storage system class: all
Show CLARiiON LUN names:
true
Path Latency Monitor: Off
Path Latency Threshold: 0 Sec.
Storage
System Class Attributes
------------ ---------Symmetrix
periodic autorestore
status = managed
CLARiiON
periodic autorestore
status = managed
Hitachi
periodic autorestore
status = managed
Invista
periodic autorestore
status = managed
HP xp
periodic autorestore
status = managed
Ess
periodic autorestore
status = managed
HP HSx
periodic autorestore
status = managed

= on
= on
= on
= on
= on
= on
= on

6. powermt display hba_mode Display PowerPath HBA

Mode
This is similar to #1, but displays whether hba is enabled or not, as shown in the last
column of the output.
# powermt display hba_mode
Symmetrix logical device count=0
CLARiiON logical device count=1

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 Q-IOs Mode
==============================================================================
1 qla2xxx
optimal
2
0
0 Enabled
2 qla2xxx
optimal
2
0
0 Enabled

7. powermt display path Display available I/O Paths.

This displays all available path for your SAN device.
# powermt display paths
Symmetrix logical device count=0
==============================================================================
----- Host Bus Adapters --------- ------ Storage System ----- I/O Paths ### HW Path
ID
Interface
Total
Dead
==============================================================================
CLARiiON logical device count=1
==============================================================================
----- Host Bus Adapters --------- ------ Storage System ----- I/O Paths ### HW Path
ID
Interface
Total
Dead
==============================================================================
1 qla2xxx
AAA00000000000
SP A4
1
0
1 qla2xxx
AAA00000000000
SP B4
1
0
2 qla2xxx
AAA00000000000
SP A5
1
0
2 qla2xxx
AAA00000000000
SP B5
1
0
Hitachi logical device count=0
==============================================================================
----- Host Bus Adapters --------- ------ Storage System ----- I/O Paths ### HW Path
ID
Interface
Total
Dead
==============================================================================
Invista logical device count=0
==============================================================================
----- Host Bus Adapters --------- ------ Storage System ----- I/O Paths ### HW Path
ID
Interface
Total
Dead
==============================================================================
HP xp logical device count=0
==============================================================================
----- Host Bus Adapters --------- ------ Storage System ----- I/O Paths ### HW Path
ID
Interface
Total
Dead
==============================================================================
Ess logical device count=0
==============================================================================
----- Host Bus Adapters --------- ------ Storage System ----- I/O Paths ### HW Path
ID
Interface
Total
Dead
==============================================================================
HP HSx logical device count=0
==============================================================================
----- Host Bus Adapters --------- ------ Storage System ----- I/O Paths ### HW Path
ID
Interface
Total
Dead
==============================================================================

8. powermt displays port_mode Display Port Status

Displays the status of the individual ports on the HBA. i.e Whether the port is enabled or
not.
# powermt display port_mode
Storage class = Symmetrix
==============================================================================
----------- Storage System ---------------- I/O Paths ---- Stats --ID
Interface
Wt_Q
Total
Dead
Q-IOs Mode
==============================================================================
Storage class = CLARiiON
==============================================================================
----------- Storage System ---------------- I/O Paths ---- Stats --ID
Interface
Wt_Q
Total
Dead
Q-IOs Mode
==============================================================================
AAA00000000000
SP
A4
256
1
0
0 Enabled
AAA00000000000
SP
B4
256
1
0
0 Enabled
AAA00000000000
SP
A5
256
1
0
0 Enabled
AAA00000000000
SP
B5
256
1
0
0 Enabled

9. powermt version Display EMC PowerPath Version

How to identify the version number of EMC PowerPath software?
# powermt version
EMC powermt for PowerPath (c) Version 5.3 (build 185)

10. powermt check Check the I/O Paths

If you have made changes to the HBAs, or I/O paths, just execute powermt check, to take
appropriate action. For example, if you have manually removed an I/O path, check
command will detect a dead path and remove it from the EMC path list.
# powermt check
Warning: storage_system I/O path path_name is dead.
Do you want to remove it (y/n/a/q)?
Note: If you want powermt to automatically remove all dead paths, without any
confirmation, execute powermt check force.

11. powermt set mode hba Forcefully set the mode for a
specific HBA
You can change the mode of a specific HBA to either standby or active using this command.
Following example, changes HBA #1s mode from active to standby.
# powermt set mode=standby hba=1

After the above command, you can see the mode for HBA#1 changed to standby, as shown
below.
# powermt display dev=all
Pseudo name=emcpowera
CLARiiON ID=AAA00000000000 [dev-server]
Logical device ID=1111111111111111111 [LUN 1]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP B, current=SP B
Array failover mode: 1
==============================================================================
---------------- Host --------------- Stor -- I/O Path - -- Stats --### HW Path
I/O Paths
Interf.
Mode
State Q-IOs Errors
==============================================================================
1 qla2xxx
sdd
SP A4
standby alive
0
0
1 qla2xxx
sde
SP B4
standby alive
0
0
2 qla2xxx
sdf
SP A5
active alive
0
0
2 qla2xxx
sdg
SP B5
active alive
0
0
Note: Path mode can also be unlic indicating that youve not registered the PowerPath
with proper License key.
Note: Some powermt commands (for example, powermt set port_disable), is restricted to
certain platform and storage type On AIX and Solaris, only Fibre channel is supported. On
HP-UX, only iSCSI and Fibre are supported. On Linux, Only iSCSI (HBAs) and Fibre are
supported.

12. powermt remove Delete an I/O Path

Use this command to remove any specific I/O path (or) a whole device.
The following example has 4 I/O Paths.
# powermt display dev=all
==============================================================================
---------------- Host --------------- Stor -- I/O Path - -- Stats --### HW Path
I/O Paths
Interf.
Mode
State Q-IOs Errors
==============================================================================
1 qla2xxx
sdd
SP A4
standby alive
0
0
1 qla2xxx
sde
SP B4
standby alive
0
0
2 qla2xxx
sdf
SP A5
active alive
0
0
2 qla2xxx
sdg
SP B5
active alive
0
0
To remove I/O Path sdd, execute the following powermt remove command.
# powermt remove dev=sdd
# powermt display dev=all
==============================================================================
---------------- Host --------------- Stor -- I/O Path - -- Stats --### HW Path
I/O Paths
Interf.
Mode
State Q-IOs Errors
==============================================================================
1 qla2xxx
sde
SP B4
standby alive
0
0
2 qla2xxx
sdf
SP A5
active alive
0
0
2 qla2xxx
sdg
SP B5
active alive
0
0

Following will remove all I/O Path for a particular device. i.e To remove /dev/emcpowera, do
the following. If the /dev/emcpowera is mounted and used by some program, following
command will not work.
# powermt remove dev=emcpowera

13. powermt config Configure PowerPath

This command checks for available EMC SAN logical devices and add those to PowerPath
configuration list. Powermt config command, sets some of the options to its default values.
For example, write throttling = off, HBA mode = active, CLARiiON policy = CLAROpt, etc.
Possible EMC SAN LUN policy values are: Adaptive, BasicFailover, CLAROpt, LeastBlocks,
LeastIos, NoRedirect, Request, RoundRobin, StreamIO, or SymmOpt.
After you execute the powermt config, if you dont like any of the default values, you should
change it accordingly.
# powermt config

14. powermt restore Make Dead I/O Path Alive

If you have dead I/O paths, and if youve done something to fix the issue, you can request
PowerPath to re-check the paths and mark it as active using powermt restore command.
When you execute powermt restore, it does an I/O path check. If a previously dead path is
alive, it will be marked as alive, and if a previously alive path is dead, it will be marked as
dead.
For some reason, if you see the default owner and the current owner of a particular LUN is
not the same storage processor, then execute the following command, which will make the
current owner of the LUN same as the default owner.
# powermt restore dev=all
Instead of dev, you can also specify class in the powermt restore command. Class can be
one of the following depending on your system.
symm Symmetrix
clariion - CLARiiON
invista Invista
ess IBM ESS
hitachi Hitachi Lightning TagmaStore
hpxp - HP StorageWorks XP, or EVA series
hphsx HP StorageWorks EMA, or MA
all All systems

15. Powermt Save and Load Save and Restore PowerPath

Configurations
powermt save Save the current Powerpath Configuration

If you are changing the PowerPath configurations for testing purpose, you can save the
current configuration using powermt save command.
Use this method to backup the current PowerPath Configurations.
# powermt save
This will save the current powermt configuration to /etc/powermt.custom file. Following is
the partial content of this file.
# cat /etc/powermt.custom
global:version:5.3.0.0.0:4.1.0
path_c:sdd:sdd:qla2xxx:0x111
path_c:sde:sde:qla2xxx:0x111
adapter: 1: 1:qla2xxx:0x111:1:0:111:0:11:0
adapter: 2: 2:qla2xxx:0x111:1:0:111:0:111:0
arrPort_c:04000000:04000000:111:111
mpext_cfg:unused:Mp:0:symm:0:0
...
...
If you want to store the current PowePath configuration to a different file, do the following.
# powermt save file=/etc/powermt.21-Aug-2010
powermt load Load a previously saved EMC PowerPath Configuration
When you are testing EMC PowerPath configuration, if you are not satisfied with the new
configuration, you can go back to the previous configuration.
For example, to restore the configuration to a specific file that you created in the above
powermt save example, do the following.
# powermt load file=/etc/powermt.21-Aug-2010