Srik1920
2 Iron

HOW TO CHECK MULTIPATHING IS WORKING OR NOT

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Hi friends,

Recently we have a director(7d processor only faulted,only used for srdf) failure in DMX 4 at DR site.Before director replacement time

we took down time from all single path servers assosciated with that director.But we did not take any down time from dual path servers.But

while replacement time,it is observed that dual path server also  faced problem in accessing lun.Later

we observed power path licensing is not done properly,so it did not work.what I want to know is,is there any method for knowing powerpath

or any multipathing software working properly or not?,other than removing cables manually to disable redundant paths and testinng it.

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anoopcr
3 Argentium

Re: HOW TO CHECK MULTIPATHING IS WORKING OR NOT

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Hi Srik,

"Unlic" means  unlicensed. The path is not licensed. If the path is not licensed there wont be any communication through this path.So when you replace the director 7,all the 4 processor become inaccessible. Here during that time there was no active path to the luns(10bA in unlicensed mode )

During  initial PowerPath installation, the license key is added after a host reboot, the PowerPath policy by default is set to Basic Failover.  After adding the license key the PowerPath policy must be manually changed to ClarOpt for CLARiiON arrays and SymmOpt for Symmetrix storage systems in order to maximize PowerPath's potential.

To Fix this unlicensed paths in powerPath issue you can follow below work around mentioned in primus solution emc135527

To resolve the issue with LUN from Symmetrix :

1.    powermt check_registration  (Make sure the license shows with full capabilities.)

2.    powermt set policy=so dev=all  (Set the Policy to SymmOpt.)

3.    powermt display dev=all  (Make sure all device paths are now licensed.)

4.    powermt save  (Save configuration.)

To resolve the issue with LUN from CLARiiON :


1.    powermt check_registration  (Make sure the license shows with full capabilities.)

2.    powermt set policy=co dev=all (Set the Policy to ClarOpt.)

3.    powermt display dev=all (Make sure all device paths are now licensed.)

4.    powermt save (Save configuration.)

To resolve the issue with LUN from Other Storage Systems :


1.    powermt check_registration  (Make sure the license shows with full capabilities.)

2.    powermt set policy=ad dev=all  (Set the correct policy.)

3.    powermt display dev=all  (Make sure all device paths are now licensed.)

4.    powermt save  (Save configuration.)

Note:

UNIX Servers: If the license key is not installed, use the emcpreg –install command.

Windows Servers: If the license key is not installed, use the emclictool.exe via the Programs Menu.

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5 Replies
dynamox
6 Thallium

Re: HOW TO CHECK MULTIPATHING IS WORKING OR NOT

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that can only be checked from the host side, "powermt display dev=all".  There should be multipath paths, all alive, correct policy ..etc.

Srik1920
2 Iron

Re: HOW TO CHECK MULTIPATHING IS WORKING OR NOT

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Hi dynamox,

can you explain the below screenshot,it is output of "powermt dispaly dev=all".for one path mode it is showing "unlic",what does it mean.

oracledbdrredonlymode2.JPG

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anoopcr
3 Argentium

Re: HOW TO CHECK MULTIPATHING IS WORKING OR NOT

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Hi Srik,

"Unlic" means  unlicensed. The path is not licensed. If the path is not licensed there wont be any communication through this path.So when you replace the director 7,all the 4 processor become inaccessible. Here during that time there was no active path to the luns(10bA in unlicensed mode )

During  initial PowerPath installation, the license key is added after a host reboot, the PowerPath policy by default is set to Basic Failover.  After adding the license key the PowerPath policy must be manually changed to ClarOpt for CLARiiON arrays and SymmOpt for Symmetrix storage systems in order to maximize PowerPath's potential.

To Fix this unlicensed paths in powerPath issue you can follow below work around mentioned in primus solution emc135527

To resolve the issue with LUN from Symmetrix :

1.    powermt check_registration  (Make sure the license shows with full capabilities.)

2.    powermt set policy=so dev=all  (Set the Policy to SymmOpt.)

3.    powermt display dev=all  (Make sure all device paths are now licensed.)

4.    powermt save  (Save configuration.)

To resolve the issue with LUN from CLARiiON :


1.    powermt check_registration  (Make sure the license shows with full capabilities.)

2.    powermt set policy=co dev=all (Set the Policy to ClarOpt.)

3.    powermt display dev=all (Make sure all device paths are now licensed.)

4.    powermt save (Save configuration.)

To resolve the issue with LUN from Other Storage Systems :


1.    powermt check_registration  (Make sure the license shows with full capabilities.)

2.    powermt set policy=ad dev=all  (Set the correct policy.)

3.    powermt display dev=all  (Make sure all device paths are now licensed.)

4.    powermt save  (Save configuration.)

Note:

UNIX Servers: If the license key is not installed, use the emcpreg –install command.

Windows Servers: If the license key is not installed, use the emclictool.exe via the Programs Menu.

View solution in original post

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sauravrohilla
3 Cadmium

Re: HOW TO CHECK MULTIPATHING IS WORKING OR NOT

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Thanks Anoop for sharing this useful information.

Srik, unlic means that you can only opt for BasicFailover policy in PP (simply menas unlicensed). If the path 7ba (from your snapshot) goes down then it PP will not route the IOs to unlic path.

regards,

Saurabh

Srik1920
2 Iron

Re: HOW TO CHECK MULTIPATHING IS WORKING OR NOT

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Hi Anoop,

Thanks for your reply.It is very useful to me.

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