Chapter 25. Configuring an Installed Linux on System z Instance

Procedure 25.1. Adding DASD Disks on IBM System z Using the VMCP Driver

1. Enable the VMCP driver:

   # modprobe vmcp

2. Use the cio_ignore command to remove the DASD from the list of ignored devices and make it visible to Linux:

   # cio_ignore -r DeviceNumber

   Replace DeviceNumber with the device number of the DASD. For example:

   # cio_ignore -r 0102

3. Link the disk to the virtual machine:

   # vmcp 'link * DeviceNumber DeviceNumber rw'

   Replace DeviceNumber with the device number of the DASD.
4. Set the device online. Use a command of the following form:

   # # chccwdev -e DeviceNumber

   Replace DeviceNumber with the device number of the DASD.
5. Verify that the disk is ready using the lsdasd command:

   # lsdasd
   Bus-ID     Status      Name      Device  Type  BlkSz  Size      Blocks
   ==============================================================================
   0.0.0100   active      dasda     94:0    ECKD  4096   2347MB    600840
   0.0.0301   active      dasdb     94:4    FBA   512    512MB     1048576
   0.0.0300   active      dasdc     94:8    FBA   512    256MB     524288
   0.0.0101   active      dasdd     94:12   ECKD  4096   2347MB    600840
   0.0.0200   active      dasde     94:16   ECKD  4096   781MB     200160
   0.0.0102   active      dasdf     94:20   ECKD  4096   2347MB    600840
   

   In the above example, device 0102 (shown as 0.0.0102 in the Bus-ID column) is being accessed as /dev/dasdf.

Procedure 25.3. Permanently Attaching DASDs as Non-root Devices

• Trigger the activation by writing to the uevent attribute of the device:

  echo add > /sys/bus/ccw/devices/device.bus,ID/uevent

  For example:

  echo add > /sys/bus/ccw/devices/0.0.021a/uevent

Procedure 25.4. Formatting a DASD

1. Wipe all existing data on the DASD using the dasdfmt command. Replace DeviceNumber with the device number of the DASD. When prompted for confirmation (as shown in the example below), type yes to proceed.

   # dasdfmt -b 4096 -d cdl -p /dev/disk/by-path/ccw-0.0.DeviceNumber
   Drive Geometry: 10017 Cylinders * 15 Heads =  150255 Tracks
   
   I am going to format the device /dev/disk/by-path/ccw-0.0.0102 in the following way:
      Device number of device : 0x4b2e
      Labelling device        : yes
      Disk label              : VOL1
      Disk identifier         : 0X0102
      Extent start (trk no)   : 0
      Extent end (trk no)     : 150254
      Compatible Disk Layout  : yes
      Blocksize               : 4096
   
   --->> ATTENTION! <<---
   All data of that device will be lost.
   Type "yes" to continue, no will leave the disk untouched: yes
   cyl    97 of  3338 |#----------------------------------------------|   2%
   

   When the progress bar reaches the end and the format is complete, dasdfmt prints the following output:

   Rereading the partition table...
   Exiting...
   

   See the dasdfmt(8) man page for information about the syntax of the dasdfmt command.
2. Use the fdasd command to write a new Linux-compatible partition table to the DASD. Replace DeviceNumber with the device number of the DASD.

   # fdasd -a /dev/disk/by-path/ccw-DeviceNumber
   auto-creating one partition for the whole disk...
   writing volume label...
   writing VTOC...
   checking !
   wrote NATIVE!
   rereading partition table...
   

   This example uses the -a option to create a single partition spanning the entire disk. Other layouts are possible; up to three partitions can be created on a single DASD. For information about the syntax of the fdasd command and available options, see the fdasd(8) man page.
3. Create a new partition with fdisk. Replace DeviceName with the device name of the DASD.

   # fdisk /dev/DeviceName

   After you execute fdisk, a series of prompts will appear in your terminal. These prompts can be used to manipulate the disk partition table, creating new partitions or editing existing one. For information about using fdisk, see the fdisk(8) man page.

Procedure 25.5. Expanding Existing Logical Volume to Use a New DASD

1. Create a new physical volume for LVM on the DASD using the pvcreate command:

   # pvcreate /dev/DeviceName

   Important

   The device name must be specified as a partition - for example, /dev/dasdf1. Do not specify the entire block device.
2. List existing physical volumes using the pvs command to verify that the physical volume has been created:

   # pvs
   PV                 VG             Fmt  Attr PSize   PFree
    /dev/dasda2        vg_local       lvm2 a--    1,29g       0
    /dev/dasdd1        vg_local       lvm2 a--    2,29g       0
    /dev/dasdf1                       lvm2 a--    2,29g    2,29g
    /dev/mapper/mpathb vgextnotshared lvm2 a--  200,00g 1020,00m
   

   As you can see in the above example, /dev/dasdf1 now contains an empty physical volume which is not assigned to any volume group.
3. Use the vgextend command to expand an existing volume group containing the volume you want to use the new DASD for:

   # vgextend VolumeGroup PhysicalVolume

   Replace VolumeGroup with the name of the volume group you are expanding, and PhysicalVolume with the name of the physical volume (for example, /dev/dasdf1).
4. Use the lvextend command to expand a logical volume you want to use the new DASD for:

   # lvextend -L +Size /dev/mapper/VolumeGroup-LogicalVolume

   For example:

   # lvextend -L +2G /dev/mapper/vg_local-lv_root
   Extending logical volume lv_root to 2,58 GiB
   Logical volume lv_root successfully resized