connect second HBA port, what to do with existing Vdisks?

[Joe_P]

Hi All,

Currently we have a server which has only 1 connection to a SAN switch (through a Qlogic HBA).
We're planning to connect the second HBA port to our other SAN switch.
After his we want to enable failover mode.

The server runs Redhat 4.4.

My question is what to do with the Vdisks which are already presented to the server through the already connected/configured HBA port?

Do these Vdisks have to be unpresented before the second HBA port is added to the Host in Command View EVA or not?

Thanks.

[Torsten.]

Setup the zone and add presentation to that HBA. Make sure to use multipath drivers/software.

[Joe_P]

Torsten,

Thanks, I get that.

We're going to configure zoning, and then add the second HBA port to the Host in Command View EVA.

If I understand correctly, the moment the second HBA port is added to the Host in CVE, the already presented Vdisks become 'visible' on the Server through that HBA port.

But the question is, will adding the second HBA port to the Host in CVE cause a problem for the already presented Vdisks?

In other words, should these Vdisks be unpresented first and presented again after adding the second HBA port to the Host in CVE?

[Ivan Ferreira · Accepted solution]

>>> If I understand correctly, the moment the second HBA port is added to the Host in CVE, the already presented Vdisks become 'visible' on the Server through that HBA port.

More or less, the disk is potentially visible, but it won't be until you do some SCSI rescan or server restart. You can use hp_rescan -a or the rescan-scsi-bus.sh script.

>>> But the question is, will adding the second HBA port to the Host in CVE cause a problem for the already presented Vdisks?

No. It wont'.

>>> In other words, should these Vdisks be unpresented first and presented again after adding the second HBA port to the Host in CVE?

No. You don't need to unpresent the vdisk. But you must keep in mind that you need to configure any multipath software. Your options are: Qlogic driver multipath or Red Hat multipath.

[Joe_P]

Ivan,

Thanks for your answer.

We'll use the Qlogic failover mode (Install -f)