19 Iscsi And The Hp P4000 San Solution; Number Of Iscsi Sessions; Virtual Ip Addresses; Requirements For Using A Virtual Ip Address - HP StorageWorks P4000 User Manual

19 iSCSI and the HP P4000 SAN Solution

The SAN/iQ software uses the iSCSI protocol to let servers access volumes. For fault tolerance and
improved performance, use a VIP and iSCSI load balancing when configuring server access to volumes.
The following concepts are important when setting up clusters and servers in the SAN/iQ software:
• "Virtual IP
• "iSNS server" on page 300
• "iSCSI load
• "Authentication
• "iSCSI and CHAP
• "About HP DSM for

Number of iSCSI sessions

For information about the recommended maximum number of iSCSI sessions that can be created in
a management group, see

Virtual IP addresses

A virtual IP (VIP) address is a highly available IP address which ensures that if a storage system in a
cluster becomes unavailable, servers can still access a volume through the other storage systems in
the cluster.
Your servers use the VIP to discover volumes on the SAN. The SAN uses the iqn from the iSCSI initiator
to associate volumes with the server.
A VIP is required for a fault tolerant iSCSI cluster configuration, using VIP load balancing or the HP
DSM for MPIO.
When using a VIP, one storage system in the cluster hosts the VIP. All I/O goes through the VIP host.
You can determine which storage system hosts the VIP by selecting the cluster, then clicking the iSCSI
tab.

Requirements for using a virtual IP address

• For standard clusters (not multi-site clusters), storage systems occupying the same cluster must be
in the same subnet address range as the VIP.
• The VIP must be routable regardless of which storage system it is assigned to.
• iSCSI servers must be able to ping the VIP when it is enabled in a cluster.
• The VIP address must be different than any storage system IPs on the network.
• The VIP address must be a static IP address reserved for this purpose.
• All iSCSI initiators must be configured to connect to the VIP address for the iSCSI failover to work
properly.
addresses" on page 299
balancing" on page 300
(CHAP)" on page 300
terminology" on page 302
MPIO" on page 304
"Configuration Summary overview" on page 151.
P4000 SAN Solution user guide 299