34 Appendix A Replacing and Upgrading FRUsA.1 Installing or Replacing DrivesBefore you install or replace drives, plan where you will be placing the disk drives. If anarray will not be fully populated with drives, be sure the drive slots contain drive traysand/or blank filler panels. For more information, see Figure 2-3 and Section 2.1.High Availability (HA) Note: A system using a single controller (DSN-5110-10.DSN-5210-10 or DSN-5410-10) and its expansion array(s) may use SAS or SATAdrives. A system using dual controllers for High Availability operation (DSN-510 for the 5110-10, DSN-520 for the 5210-10 or DSN-540 for the 5410-10)requires SAS drives be used in both the primary array and any expansionarray(s).If you anticipate upgrading to HA with the addition of a second controller,then it is recommended you install SAS drives.Also, do not mix SAS and SATA drives in the same storage system.To install a drive, use the following procedure.1. On the front of the enclosure, select an open drive slot.2. Select the right type of drive for this drive slot (see the figures above).3. Hold the drive so the LEDs are on the left and the lever is fully open. Then slide thedrive into the drive slot until the lever starts to close.Figure A-1. Installing a Drive4. Gently push the lever until it meets the latch on the left side of the drive slot and clicksinto place.Figure A-2. Securing a Drive in the Slot5. To install additional drives, repeat this procedure.