Adaptec 2268300R How are Disk Drives Identified in SAS?, What are the SAS Connection Options?

Appendix A: Introduction to SAS ● 92

How are Disk Drives Identified in SAS?

In the BIOS and in the management utilities (see Identifying Disk Drives on page 114), disk drives are identified in the following formats:

●CNX:DevY = Device Y is attached to Connector X (see Direct-attach Connections below for more information)

●BoxX:SlotX = Enclosure X is attached to a disk drive in Slot X (see Backplane Connections below for more information)

●ExpX:PhyX = Expander X is attached to Phy X (see SAS Expander Connections below for more information)

where X is the count number.

Note: Devices other than disk drives (CDROM, tape drives, etc...) are listed in order after your system disk drives.

In parallel SCSI, XX is the disk drive’s channel number, YY is the target number, and ZZ is the logical unit number (LUN).

What are the SAS Connection Options?

You can connect end devices to each other through direct cable connections and through backplane connections. When you use one or more expander devices (see page 93), you can create large configurations.

Direct-attach Connections

In a direct-attach connection, SAS or SATA disk drives are connected directly to a SAS card with SAS or mini-SAS cables. One disk drive is attached to one SAS/mini-SAS connector with one SAS/mini-SAS cable (or multiple disk drives are attached to one SAS/mini-SAS connector with one fan-out cable). The figure on page 50 shows an example of direct-attach connections.

The number of direct-attached disk drives is limited to the number of phys supported by the SAS card. (Note that there may be multiple phys within a single connector. See page 93.)

Backplane Connections

In a backplane connection, disk drives and SAS cards are attached to and communicate with each other through a system backplane.

There are two types of backplane connections, passive and active. When connecting to either backplane, it’s important to properly connect your disk drive LEDs in order to identify disk drive conditions. See About Your RAID Controller on page 17 for your RAID controller Activity LED connections and locations.

Once you have connected to a backplane, use Adaptec Storage Manager to manage your disk drives. For more information, refer to the Adaptec Storage Manager User’s Guide on the Adaptec Installation DVD.

.The number of end devices is limited to the number of slots available on the backplane. For example, the Adaptec S50 enclosure, which contains an expander, is a backplane connection that supports up to 12 SAS or SATA disk drives.