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This chapter is from the book

Administering LUNs

Many modern Oracle Solaris systems are attached directly to an external Storage Area Network (SAN) device containing several disk drives. The drives in this storage device are configured as virtual drives, and each is referred to as a logical unit. Each logical unit is identified by a number, the logical unit number or LUN. The LUN is attached to the server through a Fibre Channel connection. These LUNs appear as disk drives, just like an internal disk, but the device name is different in that it contains the device’s World Wide Name (WWN). Here’s an example:

# format<cr>
Searching for disks ... done

       0. c0t0d0 <SUN146G cyl 14087 alt 2 hd 24 sec 848>
       1. c0t1d0 <SUN146G cyl 14087 alt 2 hd 24 sec 848>
       2. c3t60A98000572D577465346D3936706348d0 <NETAPP-LUN-7330-200.00GB>
       3. c3t60A9800043346B74635A4F4371304A66d0 <NETAPP-LUN-7330-200.00GB>
       4. c3t60A9800043346B74635A4F4370767969d0 <NETAPP-LUN-7330-200.00GB>
       5. c3t60A9800043346B7448344F4371543378d0 <NETAPP-LUN-7330-1.27TB>
       6. c3t60A9800043346B7448344F4374437666d0 <NETAPP-LUN-7330-1.22TB>
Specify disk (enter its number):

For disks 2–6, the WWN is in place of the target ID field. On a fiber-attached device, the WWN is a unique identifier used to uniquely identify each LUN in a Fibre Channel network. In the previous example, the server is connected to a NetApp data storage system connected via Fibre Channel. The LUNs were identified and dynamically configured during the boot process. They can be displayed using the format command as shown in the previous example.

Use the luxadm command to scan the devices and present a list of all LUNs and their logical names as follows:

# luxadm probe<cr>
No Network Array enclosures found in /dev/es

Found Fibre Channel device(s):
  Node WWN:500a0980894b97b6 Device Type:Disk device
    Logical Path:/dev/rdsk/c3t60A98000572D577465346D3936706348d0s2
  Node WWN:500a0980894b97b6 Device Type:Disk device
    Logical Path:/dev/rdsk/c3t60A9800043346B74635A4F4371304A66d0s2
  Node WWN:500a0980894b97b6 Device Type:Disk device
    Logical Path:/dev/rdsk/c3t60A9800043346B74635A4F4370767969d0s2
  Node WWN:500a0980894b97b6 Device Type:Disk device
    Logical Path:/dev/rdsk/c3t60A9800043346B7448344F4371543378d0s2
  Node WWN:500a0980894b97b6 Device Type:Disk device
    Logical Path:/dev/rdsk/c3t60A9800043346B7448344F4374437666d0s2

Choose a logical name and display information about each individual LUN as follows:

# luxadm display /dev/rdsk/c3t60A98000572D577465346D3936706348d0s2<cr>
DEVICE PROPERTIES for disk: /dev/rdsk/c3t60A98000572D577465346D3936706348d0s2
 Vendor:          NETAPP
 Product ID:       LUN
 Revision:       7330
 Serial Num:      W-Wte4m96pcH
 Unformatted capacity: 204800.000 MBytes
 Read Cache:       Enabled
  Minimum prefetch:  0x0
  Maximum prefetch:  0x0
 Device Type:      Disk device

  Controller      /devices/pci@1,700000/SUNW,emlxs@0/fp@0,0
   Device Address        500a0981894b97b6,5
   Host controller port WWN        10000000c9729bb9
   Class                 primary
   State                 ONLINE
  Device Address         500a0981994b97b6,5
  Host controller port WWN      10000000c972a675
  Class                   secondary
  State                     ONLINE

Provide the information obtained from the luxadm display command to your storage administrator so that you create the file system on the correct LUN. It’s very important that you select the correct LUN when more than one LUN is available.

The next step is to configure a file system on the LUN. I’ll create a ZFS file system on the LUN as follows:

# zpool create pool1 c3t60A98000572D577465346D3936706348d0<cr>

For more information on creating file systems, refer to Chapter 5.

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