3Ware 9550SXU16MLB10 User Guide - Page 99

Creating a Hot Spare Note: 3ware's 9000 series RAID controllers use drive coercion so that drives from differing manufacturers and with slightly different capacities are more likely to be able to be used as spares for each other. Drive coercion slightly decreases the usable capacity of a drive that is used in redundant units. The capacity used for each drive is rounded down to the nearest GB for drives under 45 GB (45,000,000,000), and rounded down to the nearest 5 GBytes for drives over 45 GB. For example, a 44.3 GB drive will be rounded down to 44 GBytes, and a 123 GB drives will be rounded down to 120 GBytes. If you have 120 GB drives from different manufacturers, chances are that the capacity varies slightly. For example, one drive might be 122 GB, and the other 123 GB, even though both are sold and marketed as "120 GB drives". 3ware drive coercion uses the same capacity for both of these drives so that one could replace the other. Specifying a Hot Spare through 3DM If you need to add a drive to be used as the hot spare, follow the instructions under "Adding a Drive through 3DM" on page 110. To specify a hot spare after the system is booted 1 In the Available Drives section of the Maintenance Page, select the drive by checking the box next to it. 2 Click Create Unit. 3 In the dialog box that appears, select the configuration type Spare. 4 Click Ok. You will see the spare appear at the top of the page, under Unit Maintenance. www.3ware.com 93