Yuk_Chan
2 Bronze

Change to another SAN switch - AIX, powerpath, data domain

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Hi,

I am looking for some advice for the procedure for moving the FC cables connecting to AIX boxes from one Broacade switch to another.

I have a few AIX boxes running 5.3 and 6.1 connecting to CX 4-480 and Data Domain. I want to move the connecting to another switch for freeing some space in the original one. But unlike Windows or Solaris, AIX is well known for its losing of device after hardware change. So I want to have some advice.

The worst part is: due to the idea of saving, most of the servers have only one HBA.

This is the configuration:

AIX 6.1 and 5.3 with powerpath

connect to CX 4-480 via Brocade switch

Also connect to Data Domain (VTL mode) but backup by TSM

AIX 6.1 and 5.3 with powerpath

connect to CX 4-480 via Brocade switch

Also connect to Data Domain (VTL mode) but backup by NetBackup

I wish to know what to do after system reboot and FC cables plugged in. If some action can prevent the dead device, what is that?

Thanks!

Yuk Chan

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dynamox
7 Thorium

Re: Change to another SAN switch - AIX, powerpath, data domain

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with single HBA you don't have a choice to shut down the server.

With Data Domain VTL i would do the same thing, before migration delete tape devices and changer(rmdev -dl smc0, rmtX) and then rediscover again ether during reboot or with cfgmgr. If devices change you will need to update them within TSM (update path)

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dynamox
7 Thorium

Re: Change to another SAN switch - AIX, powerpath, data domain

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yes, AIX will get a new FCID and that will change its device paths. I follow this procedure emc93300 before i shutdown the host and move it to another switch. (start step 13 on new switch).

Yuk_Chan
2 Bronze

Re: Change to another SAN switch - AIX, powerpath, data domain

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Thank you and this is a very good suggestion to handle change for CX access. Based on emc93300, am I assume that system shutdown is not necesasry during change of SAN switch?

While I still have another issue of IBM TSM to Data Domain VTL? Anyone else can help?

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dynamox
7 Thorium

Re: Change to another SAN switch - AIX, powerpath, data domain

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with single HBA you don't have a choice to shut down the server.

With Data Domain VTL i would do the same thing, before migration delete tape devices and changer(rmdev -dl smc0, rmtX) and then rediscover again ether during reboot or with cfgmgr. If devices change you will need to update them within TSM (update path)

View solution in original post

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Yuk_Chan
2 Bronze

Re: Change to another SAN switch - AIX, powerpath, data domain

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Thank you!

Your suggestion is very helpful.

But there is one more thing I want to find out before doing anything actually. As I want to replace the SAN switch, I will disconnect the FC cable connecting the SPA and SPB from the original switch to the new one (they are ISL together already). I will move them one by one. I am not sure, if I do that, will the old device in AIX become a dead device and need to create a new one by ioscan?

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dynamox
7 Thorium

Re: Change to another SAN switch - AIX, powerpath, data domain

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there is no ioscan on AIX, there is cfgmgr ..you must be thinking about HPUX. If the switch that AIX is currently connected to is ISLed to the switch you will be migrating to ..then fcid will remain the same and hdiskpower devices should not change. I have had mixed results, sometimes i have had good luck and AIX/PowerPath handled failover correctly (on system with multiple HBAs) and sometimes it got completely confused so i had to varyoffvg and export it. Then i would run cfgmgr and re-import VG. If you are simply going to shutdown the host and move to the other switch, it should come up with the same hdiskpower devices.

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