Specifying A Hot Spare Through 3Dm - 3Ware 9550SXU-12 User Manual

Configuring Units

Specifying a Hot Spare through 3DM

114
In order to replace a failed drive, a hot spare must have the same or larger
storage capacity than the drive it is replacing, and must be of the same type
(SAS or SATA).
The Auto Rebuild policy allows automatic rebuilding to occur with available
drives that are not designated as spares. For more information, see "Setting
the Auto Rebuild Policy" on page 91.
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 bytes), 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 drive 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.
If you need to add a drive to be used as the hot spare, follow the instructions
under "Adding a Drive" on page 142.
To specify a hot spare after the system is booted
1 In 3DM, choose
Management > Maintenance.
2 In the Available Drives list, select the drive you want as a hot spare by
marking the checkbox in front of it's Port number.
3 Click .
Create Unit
4 In the dialog box that appears, select the configuration type
5 Click Ok .
You will see the spare appear at the top of the page, under
Maintenance .
3ware SAS/SATA RAID Software User Guide, Version 9.5.1
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Spare
Unit