Hardware requirements for geographic mirroring

If you plan to use geographic mirroring for IBM i high availability, ensure that the minimum hardware requirements are met.

  • All independent disk pool hardware requirements must be met.
  • At least two IBM i models, which can be separated geographically, are required.
  • At least two sets of disks at each site that are roughly of similar capacity are required.
  • A separate storage pool for jobs using geographic mirrored independent disk pools should be configured. Performing geographic mirroring from the main storage pool can cause the system to hang under extreme load conditions.
  • Geographic mirroring is performed when the disk pool is available. When geographic mirroring is being performed, the system value for the time of day (QTIME) should not be changed.
  • Communications requirements for independent disk pools are critical because they affect throughput.
  • Geographic mirroring traffic is dispersed round robin across the potentially multiple communication lines available to it. It is recommended that if multiple lines are provided for geographic mirroring, that those lines be of similar speed and capacity.
  • It is recommended that a separate communication line be used for the clustering heartbeat to prevent contention with the geographic mirroring traffic.