Talk:OPS235 Lab 4 - Fedora17

When the students are done lab 3, they should have:

• fedora1

 This VM has a GUI and no free space in the VG.

 VG         #PV #LV #SN Attr   VSize VFree
 vg_fedora1   1   2   0 wz--n- 9.80G    0 

 LV      VG         Attr   LSize   
 lv_root vg_fedora1 -wi-ao   8.83G                                      
 lv_swap vg_fedora1 -wi-ao 992.00M                                      

 PV         VG         Fmt  Attr PSize PFree
 /dev/vda2  vg_fedora1 lvm2 a-   9.80G    0 

• fedora2

 This VM has a GUI and free space in the VG.

 VG         #PV #LV #SN Attr   VSize VFree
 vg_fedora2   1   3   0 wz--n- 9.80G 3.95G

 LV      VG         Attr   LSize    
 lv_home vg_fedora2 -wi-ao 1000.00M                                      
 lv_root vg_fedora2 -wi-ao    3.91G                                      
 lv_swap vg_fedora2 -wi-ao  992.00M                                      

 PV         VG         Fmt  Attr PSize PFree
 /dev/vda2  vg_fedora2 lvm2 a-   9.80G 3.95G

• fedora3

 This VM has no GUI installed.

 VG         #PV #LV #SN Attr   VSize VFree
 vg_fedora3   1   3   0 wz--n- 9.80G 3.83G

 LV      VG         Attr   LSize   
 lv_home vg_fedora3 -wi-ao   1.00G                                      
 lv_root vg_fedora3 -wi-ao   4.00G                                      
 lv_swap vg_fedora3 -wi-ao 992.00M                                      

 PV         VG         Fmt  Attr PSize PFree
 /dev/vda2  vg_fedora3 lvm2 a-   9.80G 3.83G

• host (disk pack)

 Four PVs, minimum VG size 60G
 Single filesystem on vg_main/root, size 50G
 At least 10G available space in VG

 20% of disk space unallocated (min 15G)

Recommendations for the revised LVM lab:

• Start with the GUI tool, which may help them visualize what is happening.
• Continue with performing exactly the same operations on another VM using command-line tools.
• Next, the will add a second virtual disk to a VM and migrate /home to its own filesystem.
• On the real system (disk pack), they will add a partition as a PV and grow the root filesystem (minimal risk).
• They will then migrate a VM from its original virtual disk to a new, slightly larger virtual disk.

Investigation 1: How are LVMs managed using system-config-lvm?

• On fedora2, perform some LVM operations using the system-config-lvm graphical tool:
  • Grow the home filesystem to 2G
  • Create a new 2G LV containing an ext4 filesystem named lv_archive and mount it at /archive
  • Backup /etc into /archive
  • Shrink lv_archive to 1G
  • Try shrinking / and observe that it is not permitted

Investigation 2: How are LVMs managed from the command line?

• Repeat the operations from Investigation 1, using fedora3:
  • Grow the home filesystem to 2G
  • Create a new 2G LV containing an ext4 filesystem and mount it at /archive (lvcreate, mkfs, mount, edit fstab, reboot to confirm automatic mount)
  • Backup /etc into /archive
  • Shrink lv_archive to 1G (umount, resize2fs, lvreduce, resize2fs, mount)
  • Try shrinking / and observe that it is not permitted

Investigation 3: How can a PV be added to an existing VG?

• Provision fedora1 with an additional 5G virtual disk
• Add that virtual disk to the existing volume group
• Create lv_home (1G), and migrate /home onto it (lvcreate, mkfs, mount, mv, rm, umount, edit fstab, mount)

Investigation 4: How can I use LVM to manage storage on my disk pack?

• On the host (disk pack):
  • Create a new logical partition (minimum 5G, leaving at least 10G free space in the extended partition)
  • Add that partition as a PV into the existing VG
  • Grow the root filesystem to fill the available space (this will provide sufficient space for Investigation 5)

Investigation 5: How can I migrate data off a failing disk or to a larger disk?

• Migrate fedora3 from one virtual disk to another:
  • Add a 12G virtual disk to fedora3
  • Partition that second disk in a manner similar to the first disk.
  • Copy the /dev/vda1 contents to /dev/vdb1.
  • Add the remaining space on /dev/vdb to the existing VG.
  • Migrate the data off the first disk onto the second.
  • Remove the first disk from the volume group.
  • Install grub on the second disk.
  • Shut down the VM.
  • Remove the first virtual disk from the VM.
  • Start up the VM from the new virtual disk.