I am trying to find additional information on how Netapp single_image mode works in a clustered environment as it pertains to pathing. Single_image mode pulls all the WWPN's from the Netapp cluster and presents it to the SAN as one WWNN. What I would like to know is how paths are determined from hosts to cluster nodes if no target portals are defined?
Hey Mike,
On 4/16/07, Mike Ball MBall@datalink.com wrote:
I am trying to find additional information on how Netapp single_image mode works in a clustered environment as it pertains to pathing. Single_image mode pulls all the WWPN's from the Netapp cluster and presents it to the SAN as one WWNN. What I would like to know is how paths are determined from hosts to cluster nodes if no target portals are defined?
There will be multiple paths available (at least 2, one for ClusterA, one for ClusterB) and you generally will need host-based path selection software to select the active one.
Some software selects on 'Most Recently Used', other selects on fixed path, this may vary per multipathing-software.
one caveat, based on my experience
the host based software will see all paths to the filer as equal, so if you hit the WWPN on the "other" head of the cluster, you will get an error message and an ASUP. It is annoying, and as far as I know, not a problem.
Jack
Nils Vogels wrote:
Hey Mike,
On 4/16/07, Mike Ball MBall@datalink.com wrote:
I am trying to find additional information on how Netapp single_image mode works in a clustered environment as it pertains to pathing. Single_image mode pulls all the WWPN's from the Netapp cluster and presents it to the SAN as one WWNN. What I would like to know is how paths are determined from hosts to cluster nodes if no target portals are defined?
There will be multiple paths available (at least 2, one for ClusterA, one for ClusterB) and you generally will need host-based path selection software to select the active one.
Some software selects on 'Most Recently Used', other selects on fixed path, this may vary per multipathing-software.
-
Jack Lyons -
Mike Ball -
Nils Vogels