The current architecture of the open-iscsi tools prevents there from being more than one iSCSI session between any given iface record and a specific target portal.
For easier configuration of multipath setups, it would be nice to be able to create multiple iSCSI sessions from a single iface record. The alternative, which works with version 2.0.871 and later, is to create multiple iface records, each corresponding to the same HBA, and initiate a single iSCSI session from each. This works but is a bit cumbersome. This patchset introduces a new commandline syntax that takes an existing iSCSI session and creates a new session, using exactly the same node, portal, and iface record as the specified session. This uses the 'new' operation in the 'session' mode, a syntax which was previously allowed but had no real purpose. Example: # iscsiadm -m session tcp: [4] <portal> <target> # iscsiadm -m session -r 4 -o new Logging in to [iface: iface0, target: <target>, portal: <portal>] (multiple) Login to [iface: iface0, target: <target>, portal: <portal>] successful. # iscsiadm -m session tcp: [4] <portal> <target> tcp: [5] <portal> <target> The internal plumbing changes needed to achieve this are fairly minimal, and consists of two main conceptual changes: - Add a 'multisession' flag to session_rec_t which instructs iscsid to bypass the normal check it performs which prevents multiple sessions from the same iface. - Add session-specific information to session_rec_t which is populated in session mode when '-r' is specified. This session ID is then passed around with all matching records, and limits the operation of exec_node_op to only act on the specific session specified by the user. This is required because the current implementation of exec_node_op relies on the implicit 1:1 sesion-to-iface relationship. -- Jim Ramsay -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.
