AMCC 9500S User Manual

Chapter 1. Introduction to the 3ware Command Line Interface

18

Through drive coercion, the capacity used for each drive is rounded down so 
that drives from differing manufacturers are more likely to be able to be used 
as spares for each other. 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 GB for drives over 45 GB. For example, a 44.3 GB 
drive will be rounded down to 44 GB, and a 123 GB drive will be rounded 
down to 120 GB. For more information, see the discussion of drive coercion 
under “Creating a Hot Spare” on page 108.

Windows 2000, Windows XP (32-bit), Linux 2.4, and FreeBSD 4.x, do not 
currently recognize unit capacity in excess of 2 TB. 

If the combined capacity of the drives to be connected to a unit exceeds 2 
Terabytes (TB), you can enable auto-carving when you configure your units. 

Auto-carving divides the available unit capacity into multiple chunks of 2 TB 
or smaller that can be addressed by the operating systems as separate 
volumes. The carve size is adjustable from 1024 MB to 2048 MB (default) 
prior to unit creation.

If a unit over 2 TB was created prior to enabling the auto-carve option, its 
capacity visible to the operating system will still be 2TB; no additional 
capacity will be registered. To change this, the unit has to be recreated.

For more information, see “Using Auto-Carving for Multi LUN Support” on 
page 91.

RAID 50 

(number of drives - number of groups of drives) X (capacity of the 
smallest drive)