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Controller function attributes

Compare important attributes of controller functions.

Table 1. SAS controller functions
Controller functions	HA two-system RAID configuration	HA two-system JBOD configuration	HA single-system RAID configuration
512 bytes per sector disks supported	No¹	Yes	No¹
528 bytes per sector disks supported	Yes	No	Yes
Mirrored write cache between controllers (for controllers which have write cache)	Yes		Yes
Mirrored RAID parity footprints between controllers	Yes		Yes
Dual paths to disks	Yes	No	Yes
Target mode initiator device support	Yes	No	No
Only IBM® qualified disk drives supported	Yes	Yes	Yes
Only IBM qualified disk expansion drawer supported	Yes	Yes	Yes
Tape or optical devices supported	No	No	No
Boot support	No	No	Yes
Operating mode²	Primary adapter or secondary adapter³	Stand-alone adapter³	Primary adapter or secondary adapter³
Preferred dual initiator operating mode²	No preference or primary³	No preference³	No preference or primary³
Dual initiator configuration²	Default³	JBOD HA single path³	Default³
Manage HA access characteristics⁴	Yes	No	Yes
512 bytes per sector disks are not to be used functionally, but will be available to be formatted to 528 bytes per sector. Can be viewed by using the Change/Show SAS Controller screen. This option can be set by using the Change/Show SAS Controller screen. For information on managing the HA access characteristics for a disk array, see HA access optimization.

Last updated: Thu, October 10, 2013