Red Hat ENTREPRISE LINUX 5 Installation Manual page 257

Procedure 22.1. Bringing a disk online
1. Use the cd command to change to the /sys/ directory that represents that volume:
# cd ­/sys/bus/ccw/drivers/dasd­eckd/0.0.4b2e/
# ls ­­l
total 0
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 availability
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 cmb_enable
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 cutype
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 detach_state
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 devtype
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 discipline
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 online
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 readonly
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 use_diag
2. Next, check to see if it is already online:
# cat online
0
3. If it is not online, run the following command to bring it online:
# echo 1 > online
# cat online
1
4. Verify which block devnode it is being accessed as:
# ls ­­l
total 0
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 availability
lrwxrwxrwx 1 root root
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 cmb_enable
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 cutype
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 detach_state
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 devtype
­r­­r­­r­­ 1 root root 4096 Aug 25 17:04 discipline
­rw­r­­r­­ 1 root root
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 readonly
­rw­r­­r­­ 1 root root 4096 Aug 25 17:04 use_diag
As shown in this example, device 4B2E is being accessed as /dev/dasdb.
As an alternative, the recommended method for bringing a disk online (automatically) is to use the
following simple command:
# chccwdev ­­e 4b2e
Once the disk is online, change back to the /root directory and format the device:
# cd
# dasdfmt ­­b 4096 ­­d cdl ­­f ­/dev/dasdb ­­l LX4B2E ­­p ­­y
cyl 97 of 3338 ­|#­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­|
0 Aug 25 17:07 block ­­> ­../../../../block/dasdb
0 Aug 25 17:04 online
Adding DASD
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