HP P4000 9.0 HP StorageWorks P4000 SAN Solution User Guide - Page 299

iSCSI and the HP P4000 SAN Solution, Number of iSCSI sessions, Virtual IP addresses, Requirements

Page 299 highlights

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 addresses" on page 299 • "iSNS server" on page 300 • "iSCSI load balancing" on page 300 • "Authentication (CHAP)" on page 300 • "iSCSI and CHAP terminology" on page 302 • "About HP DSM for MPIO" on page 304 Number of iSCSI sessions For information about the recommended maximum number of iSCSI sessions that can be created in a management group, see "Configuration Summary overview" on page 151. 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. P4000 SAN Solution user guide 299

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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 addresses
on page 299
iSNS server
on page 300
iSCSI load balancing
on page 300
Authentication (CHAP)
on page 300
iSCSI and CHAP terminology
on page 302
About HP DSM for MPIO
on page 304
Number of iSCSI sessions
For information about the recommended maximum number of iSCSI sessions that can be created in
a management group, see
Configuration Summary overview
on page 151.
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.
P4000 SAN Solution user guide
299