HP EVA P6550 HP P6300/P6500 EVA User Guide (5697-2486, September 2013) - Page 36

2 P63x0/P65x0 EVA operation Best practices For useful information on managing and configuring your storage system, see the HP P6300/P6500 Enterprise Virtual Array configuration best practices white paper available at: http://h18006.www1.hp.com/storage/arraywhitepapers.html Operating tips and information Reserving adequate free space To ensure efficient storage system operation, reserve some unallocated capacity, or free space, in each disk group. The recommended amount of free space is influenced by your system configuration. For guidance on how much free space to reserve, see the HP P6300/P6500 Enterprise Virtual Array configuration best practices white paper. Using SAS-midline disk drives SAS-midline drives are designed for lower duty cycle applications such as near online data replication for backup. Do not use these drives as a replacement for EVA's high performance, standard duty cycle, Fibre Channel drives. This practice could shorten the life of the drive. Failback preference setting for HSV controllers Table 7 (page 36) describes the failback preference setting for the controllers. Table 7 Failback preference settings Setting No preference Point in time At initial presentation On dual boot or controller resynch On controller failover On controller failback Path A - Failover Only At initial presentation On dual boot or controller resynch On controller failover On controller failback Path B - Failover Only At initial presentation On dual boot or controller resynch Behavior The units are alternately brought online to Controller 1 or to Controller 2. If cache data for a LUN exists on a particular controller, the unit will be brought online there. Otherwise, the units are alternately brought online to Controller 1 or to Controller 2. All LUNs are brought online to the surviving controller. All LUNs remain on the surviving controller. There is no failback except if a host moves the LUN using SCSI commands. The units are brought online to Controller 1. If cache data for a LUN exists on a particular controller, the unit will be brought online there. Otherwise, the units are brought online to Controller 1. All LUNs are brought online to the surviving controller. All LUNs remain on the surviving controller. There is no failback except if a host moves the LUN using SCSI commands. The units are brought online to Controller 2. If cache data for a LUN exists on a particular controller, the unit will be brought online there. 36 P63x0/P65x0 EVA operation