User manual IBM I VIRTUALIZATION READ ME FIRST 7-9-2010

[. . . ] IBM i Virtualization and Open Storage Read-me First Vess Natchev Cloud | Virtualization | Power Systems IBM Rochester, MN vess@us. ibm. com July 9th, 2010 1 This "read-me first" document provides detailed instructions on using IBM i 6. 1 virtualization and connecting open storage to IBM i. It covers prerequisites, supported hardware and software, planning considerations, install and post-install tasks such as backups. The document also contains links to many additional information sources. Table of Contents 1. IBM i using open storage as a client of the Virtual I/O Server (VIOS) 1. 3. [. . . ] The MPIO driver can be used with any storage subsystem which VIOS supports and is included in a default install. In this case, configuration is required only on the storage subsystem in order to connect a single set of LUNs to both ports on a Fibre Channel adapter owned by VIOS. This multi-path method can be configured in two ways: round-robin, or failover. For storage systems like XIV and DS8000 that support active-active multi-path connections, either method is allowed. Path failover will use one path and leave the other idle until the first path fails, while round-robin will always attempt to use both paths if available to maximize throughput. For 24 systems that only support active-passive connections, such as IBM's DS3000, DS4000, and DS5000 subsystems, failover is the only method allowed. The access method can be configured on a per-LUN basis from the VIOS command line via a Telnet or SSH session. To show the current multi-path algorithm: · lsdev ­dev hdiskX ­attr algorithm To change the multi-path algorithm: · · chdev ­dev hdiskX ­attr algorithm=round_robin, or chdev ­dev hdiskX ­attr algorithm=fail_over These commands must be repeated for each hdisk. Redundant VIOS LPARs with client-side MPIO Beginning with IBM i 6. 1 with Licensed Internal Code (LIC) 6. 1. 1, the IBM i Virtual SCSI (VSCSI) client driver supports MPIO through two or more VIOS partitions to a single set of LUNs (up to a maximum of 8 VIOS partitions). This multi-path configuration allows a VIOS partition to fail or be brought down for service without IBM i losing access to the disk volumes since the other VIOS partition(s) remain active. The following diagram illustrates the new capability for IBM i: 25 Note that as with dual VIOS LPARs and IBM i mirroring, a VSCSI connection from IBM i to both VIOS partitions is required. On the storage subsystem, it is recommended to create a host for each VIOS containing the World-wide Port Names (WWPNs) of all Fibre Channel adapters in that LPAR, and then create a host group comprising those VIOS hosts. A single set of LUNs for IBM i can then be created and mapped to the host group, giving both VIOS LPARs access to the LUNs. Configuring redundant VIOS LPARs with client-side MPIO does not preclude using MPIO within a VIOS for a higher level of resiliency, as described in the previous section. For storage systems such as DS8000 and XIV, these connections are typically shared via the round-robin access as described above, so it is good practice to have two or more connections to each VIOS partition. For DS3000, DS4000 and DS5000 with dual controllers, a connection must be made to both controllers to allow an active and a failover path. When the volumes are created on these systems, the host OS type should be set to DEFAULT or AIX (not AIX ADT/AVT, or failover/failback oscillations could occur). For all storage systems, it is recommended that the fabric configuration uses separate dedicated zones and FC cables for each connection. In addition to the VSCSI and storage subsystem configuration, there are several VIOS settings that must be changed. These must be set via a Telnet or SSH session on both VIOS partitions. The first group of settings is applied to each of the fscsiX devices being used. To show the current fscsiX devices: · lspath Set the fast fail and dynamic tracking attributes on these devices: · · chdev ­dev fscsiX ­attr fc_err_recov=fast_fail ­perm chdev ­dev fscsiX ­attr dyntrk=yes ­perm Next, restart VIOS. [. . . ] Rates and offerings are subject to change, extension or withdrawal without notice. IBM is not responsible for printing errors in this document that result in pricing or information inaccuracies. All prices shown are IBM's United States suggested list prices and are subject to change without notice; reseller prices may vary. IBM hardware products are manufactured from new parts, or new and serviceable used parts. [. . . ]