Configuring the system to create shared storage pools
Learn about configuring the system to create Virtual I/O Server (VIOS) shared storage pools.
- Cluster: 63
- Storage pool: 127
- Failure group: 63
- Logical unit: 127
Configuring the VIOS logical partitions
- There must be at least one CPU and one physical CPU of entitlement.
- The logical partitions must be configured as VIOS logical partitions.
- The logical partitions must consist of at least 4 GB of memory.
- The logical partitions must consist of at least one physical Fibre Channel adapter.
- The rootvg device for a VIOS logical partition cannot be included in storage pool provisioning.
- The associated rootvg device must be installed with VIOS Version 2.2.2.0, or later.
- The VIOS logical partition must be configured with sufficient number of virtual server Small Computer Serial Interface (SCSI) adapter connections required for the client logical partitions.
- The VIOS logical partitions in the cluster require access to all the SAN-based physical volumes in the shared storage pool of the cluster.
Configuring client logical partitions
Configure client logical partitions with the following characteristics:
- The client logical partitions must be configured as AIX® or Linux client systems.
- They must have at least 1 GB of minimum memory.
- The associated rootvg device must be installed with the appropriate AIX or Linux system software.
- Each client logical partition must be configured with a sufficient number of virtual SCSI adapter connections to map to the virtual server SCSI adapter connections of the required VIOS logical partitions.
You can define more client logical partitions.
Storage provisioning
When a cluster is created, you must specify one physical volume for the repository physical volume and at least one physical volume for the storage pool physical volume. The storage pool physical volumes are used to provide storage to the actual data generated by the client partitions. The repository physical volume is used to perform cluster communication and store the cluster configuration. The maximum client storage capacity matches the total storage capacity of all storage pool physical volumes. The repository disk must have at least 1 GB of available storage space. The physical volumes in the storage pool must have at least 20 GB of available storage space in total.
Use any method that is available for the SAN vendor to create each physical volume with at least 20 GB of available storage space. Map the physical volume to the logical partition Fibre Channel adapter for each VIOS in the cluster. The physical volumes must only be mapped to the VIOS logical partitions connected to the shared storage pool.
Cluster communication mode
In VIOS 2.2.3.0 or later, by default, the shared storage pool cluster is created in a unicast address mode. In earlier VIOS versions, the cluster communication mode is created in a multicast address mode. When the cluster versions are upgraded to VIOS Version 2.2.3.0, the communication mode changes from multicast address mode to unicast address mode as part of rolling upgrade operation.
Failure group
Failure group refers to one or more physical disks that belong to one failure domain. When the system selects a mirrored physical partition layout, it considers the failure group as a single point of failure. For example, a failure group can represent all the disks that are the children of one particular adapter (adapterA versus adapterB), or all the disks that are present on one particular SAN (sanA versus sanB), or all the disks that are present in one particular geographic location (buildingA versus buildingB).
Shared storage pool mirroring
The data in the shared storage pool can be mirrored across multiple disks within a tier. In other words, it cannot be mirrored across tiers. The pool can withstand a physical disk failure by using the disk mirrors. During disk failures, SSP mirroring provides a better reliability for the storage pool. Therefore, mirroring provides higher reliability and storage availability in the shared storage pool. The existing non-mirrored shared storage pool can be mirrored by providing a set of new disks that matches the capacity of the original failure group. All new disks belong to the new failure group.
If one or more disks or partitions of a mirrored pool fail, you will receive alerts and notifications from the management console. When you receive alerts or notifications, you must replace the disk that failed with another functional disk. When the disk functions again or if the disk is replaced, the data is resynchronized automatically.