EMC PowerPath PowermtCommand Examples – Display, Check, Remove, Config, Restore

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 anyarguments), 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 path’s each. qla2xxx indicates that it is using the Q-Logic HBA card.

This also indicates that the connectedEMC 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 logica ldevice count=0

HP HSx logical device count=0

===================================================================

----- Host BusAdapters ---------  ------ 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

CLARiiONID=AAA00000000000 [dev-server]

Logical deviceID=1111111111111111111 [LUN 1]

state=alive;policy=CLAROpt; priority=0; queued-IOs=0

Owner:default=SP B, current=SP B       Arrayfailover 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

Pseudoname=emcpowerb

CLARiiONID=AAA00000000000 [dev-server]

Logical deviceID=2111111111111111111 [LUN 2]

state=alive;policy=CLAROpt; priority=0; queued-IOs=0

Owner:default=SP A, current=SP A       Arrayfailover 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 thefollowing:

·        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

Pseudoname=emcpowera

CLARiiONID=AAA00000000000 [dev-server]

Logical deviceID=1111111111111111111 [LUN 1]

state=alive;policy=CLAROpt; priority=0; queued-IOs=0

Owner:default=SP B, current=SP B       Arrayfailover 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       SPB5     active  alive     0      0

If the device is not available, you’ll get a “Bad dev value” as shown below.

# powermt display dev=emcpowerc

Bad dev value emcpowerc, or not underPowerpath control.

4. powermt check_registration – Display PowerPath RegistrationKey / Status

If you’ve lost the Power Path registration key that you’ve 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 arrayoptions 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= on

                      status = managed

       CLARiiON      periodic autorestore= on

                      status = managed

       Hitachi       periodic autorestore= on

                      status = managed

       Invista       periodic autorestore= on

                      status = managed

       HP xp         periodic autorestore= on

                      status = managed

       Ess           periodic autorestore= on

                      status = managed

       HP HSx        periodic autorestore= on

                      status = managed

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.

# powermtdisplay 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 BusAdapters ---------  ------ 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.

# powermtdisplay paths

Symmetrixlogical device count=0

===================================================================

----- Host BusAdapters --------- ------ Storage System -----    - I/O Paths -

###  HW Path                           ID          Interface     Total   Dead

===================================================================

CLARiiON logical device count=1

===================================================================

----- Host BusAdapters --------- ------ 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 BusAdapters --------- ------ Storage System -----    - I/O Paths -

###  HW Path                           ID          Interface     Total   Dead

===================================================================

Invista logical device count=0

===================================================================

----- Host BusAdapters --------- ------ Storage System -----    - I/O Paths -

###  HW Path                           ID          Interface     Total   Dead

===================================================================

HP xp logical device count=0

===================================================================

----- Host BusAdapters --------- ------ Storage System -----    - I/O Paths -

###  HW Path                           ID          Interface     Total   Dead

===================================================================

Ess logicaldevice count=0

===================================================================

----- Host BusAdapters --------- ------ Storage System -----    - I/O Paths -

###  HW Path                           ID          Interface     Total   Dead

===================================================================

HP HSx logical device count=0

===================================================================

----- Host BusAdapters --------- ------ 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.

# powermtdisplay port_mode

Storage class =Symmetrix

===================================================================

-----------Storage System ---------------     -- I/OPaths --   --- Stats ---

    ID              Interface         Wt_Q      Total   Dead    Q-IOs  Mode

===================================================================

Storage class =CLARiiON

===================================================================

-----------Storage System ---------------     -- I/OPaths --   --- 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 ofEMC 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 HBA’s,or I/O paths, just execute powermt check, to take appropriate action. Forexample, if you have manually removed an I/O path, check command will detect adead path and remove it from the EMC path list.

# powermt check

 Warning: storage_system I/O path path_name isdead.

      Do you want to remove it (y/n/a/q)?

Note: If you want powermt toautomatically remove all dead paths, without any confirmation, execute “powermtcheck force”.

11. powermt set mode hba – Forcefully set the mode for aspecific HBA

You can change the mode of a specificHBA to either standby or active using this command. Following example, changesHBA #1′s mode from active to standby.

# powermt set mode=standby hba=1

After the above command, you can see themode for HBA#1 changed to standby, as shown below.

# powermtdisplay dev=all

Pseudoname=emcpowera

CLARiiONID=AAA00000000000 [dev-server]

Logical deviceID=1111111111111111111 [LUN 1]

state=alive;policy=CLAROpt; priority=0; queued-IOs=0

Owner:default=SP B, current=SP B       Arrayfailover 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 you’ve not registered the PowerPath with proper License key.

Note: Some powermt commands (forexample, powermt set port_disable), is restricted to certain platform andstorage 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 aresupported.

12. powermt remove – Delete an I/O Path

Use this command to remove any specificI/O path (or) a whole device.

The following example has 4 I/O Paths.

# powermtdisplay 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 removedev=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 notwork.

# powermt remove dev=emcpowera

13. powermt config – Configure PowerPath

This command checks for available EMCSAN logical devices and add those to PowerPath configuration list. Powermtconfig command, sets some of the options to it’s 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 don’t 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 you’ve 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, itdoes 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 ofthis 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 savefile=/etc/powermt.21-Aug-2010

powermt load – Load a previously saved EMC PowerPathConfiguration

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 loadfile=/etc/powermt.21-Aug-2010