            Adavanced Functions Help

o The second and third options allow you to BACKUP
  or RESTORE your disk array configuration to or
  from a diskette.  Because of the dynamic changes
  in the configuration of your disk array occur due
  to hot-spare drive replacement, the configuration
  backup information in the diskette might be
  different from that in the adapter.  It is
  important that you back up the disk array
  configuration information frequently, to keep the
  backup information in the diskette current.

o Select CHANGE WRITE POLICY to configure a logical
  drive of an array to work in either the
  write-through mode or the write-back mode.  In the
  write-back mode, the completion status is sent
  before the data is actually written to the drives.
  Write-back mode generally provides higher
  performance with increased risk of data loss in
  the event of power failure.  In Write-through mode
  completion status is sent after the data is
  written to the drives.

o CHANGE RAID PARAMETERS allows you fine tune the
  RAID subsystem for optimal performance if the RAID
  Controller supports this function.

  Stripe Unit Size:  This parameters should be
  chosen such that the stripe-unit size is close
  to the size of the system I/O requests.  The
  default is set to 8K data bytes.
     ┌────────────────────────────────────┐
     │WARNING:  Once a stripe unit is     │
     │chosen and data is stored in the    │
     │logical drives, the stripe unit     │
     │cannot be changed without destroying│
     │data in the logical drives.         │
     └────────────────────────────────────┘

  Rebuild Priority:  This parameter sets the
  priority of the execution order of the
  rebuild I/O requests with respect to system I/O
  requests.  The Rebuild Priority can be changed
  without affecting data in the logical drives.

  Parity Placement:  This parameter defines how
  parity is placed in the disk array with respect to
  data.  Depending on the workload environment there
  may be difference in performance between the Left
  Symmetric(LS) and Right Asymmetric(RA) parity
  placement.
     ┌──────────────────────────────────────┐
     │WARNING:  Once a parity placement     │
     │scheme is chosen and data is stored in│
     │the logical drives, it cannot be      │
     │changed without destroying data in the│
     │logical drives.                       │
     └──────────────────────────────────────┘

  Read Ahead:  This parameter turns on or off the
  cache read ahead up to the end of stripe unit.
  The Read Ahead can be changed without destroying
  data in the logical drives.

o Select FORMAT DRIVE to perform a low-level format
  on the drive.  You can only format a ready (RDY),
  offline (OFL),or unformatted (UFM) drive.  A low
  level format destroys all data in the drive.
