hdisk3 hdisk7 hdisk4 hdisk8 # # check mirror state # lsvg -l test_vg_1 test_vg_1: LV NAME TYPE LPs PPs PVs LV STATE MOUNT POINT test_lv_1 jfs2 3096 6192 8 open/stale /test/preferred_read loglv00 jfs2log 1 1 1 open/syncd N/A # # the mirror is stale, synchronize it # # this command will take some time depending on volume size # syncvg -P 32 -v test_vg_1 # # check mirror state # lsvg -l test_vg_1 test_vg_1: LV NAME TYPE LPs PPs PVs LV STATE MOUNT POINT test_lv_1 jfs2 3096 6192 8 open/syncd /test/preferred_read loglv00 jfs2log 1 1 1 open/syncd N/A # # turn VG quorum off # # always check your business needs, if VG quorum should be enabled or disabled # # do this to ensure the VG will not go offline if a quorum of disks goes missing # chvg -Q n test_vg_1 # # check VG state # lsvg test_vg_1 VOLUME GROUP: test_vg_1 VG IDENTIFIER: 00f6600100004c00000001464e967f3d VG STATE: active PP SIZE: 64 megabyte(s) . OPEN LVs: 2 QUORUM: 1 (Disabled) . Now, the file system data is mirrored onto two separate physical locations. The first copy is on  spinning disk; the second copy is on the FlashSystem 900. IBM AIX LVM sets the scheduling policy for reads and writes to the storage systems. If you  use mirrored logical volumes, the following scheduling policies for writing to disk can be set  for a logical volume with multiple copies:  Performs writes to multiple copies or mirrors in order. The multiple physical partitions that  represent the mirrored copies of a single logical partition are designated primary,  secondary, and tertiary.  In sequential scheduling, the physical partitions are written to in sequence. The system  waits for the write operation for one physical partition to complete before starting the write  operation for the next partition. When all write operations are complete for all mirrors, the  write operation is complete. Simultaneously starts the write operation for all the physical partitions in a logical partition.  When the write operation to the physical partition that takes the longest to complete  finishes, the write operation is complete. Specifying mirrored logical volumes with a  parallel scheduling policy might improve I/O read-operation performance because multiple  178  Implementing IBM FlashSystem 900 Model AE3 GLYPH<SM590000> Parallel scheduling policy (“p”) GLYPH<SM590000> Sequential scheduling policy (“s”) Setting the correct read and write policy