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→Logical Volume Management (Introduction)
'''LVM''' ('''Logical Volume Management''') is used to manage hard disk drives / partitions for Unix/Linux systems. LVM provides more flexibility than just working with hard disks / hard disk partitions. '''Volume Groups''' are areas used to define '''Physical Volumes''' (i.e. hard disks, disk partitions, or other forms of storage devices). '''Logical Volumes''' are then used to relate directories (mount points) to a specific physical volume or for a "range" or "span" of physical volumes.
Therefore, LVM allows more flexibility and growth potential for Linux systems (for example, having Logical volumes span multiple hard disks). Fedora CentOS uses LVM by default upon installation. Other Linux distributions may provide the capacity to install LVM, or later install and then use Logical Volume Management.
'''Although the concept of LVM is simple, it takes practice and preparation (or "thinking ahead") in order to correctly use this valuable tool'''. It is important for students to gain an understanding of LVM, and how to manage their file-systems filesystems using LVM. It is recommended for students to read the following resource prior to this lab and/or return to the following resource while performing this lab: [[Logical Volume Management]] At this point, having completed [[OPS235 Lab 2- CentOS6|Lab 2]] you should have roughly the following disk storage setup:<br /> ('''Note:''' These results are output from the '''vgs''', '''lvspvs''', and '''pvslvs''' commands that provide volume group, physical volume and logical volume information for each of the virtual machines that you created in lab2. Before proceeding, check these values with your own system to see if you are generally "on the right track".<br /><br />)
* '''fedora1centos1'''
VG #PV #LV #SN Attr VSize VFree
PV VG Fmt Attr PSize PFree
/dev/vda3 vg_fedora1 vg_centos1 lvm2 a-- 9.50g 0
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
lv_root vg_fedora1 vg_centos1 -wi-ao 8.03g lv_swap vg_fedora1 vg_centos1 -wi-ao 1.47g
* '''fedora2centos2'''
VG #PV #LV #SN Attr VSize VFree
PV VG Fmt Attr PSize PFree
/dev/vda3 vda2 vg_fedora2 vg_centos2 lvm2 a-- 1419.50g 351g 7.25g77g
LV VG Attr LSize Pool Origin SnapData% Move Log CopyCpy% Sync Convert lv_home vg_fedora2 vg_centos2 -wi-ao ---- 1.97g 95g lv_root vg_fedora2 vg_centos2 -wi-ao ---- 7.81g lv_swap vg_fedora2 vg_centos2 -wi-ao ---- 1.47g 97g
* '''fedora3 centos3 (Note: This VM has no GUI installed)'''
VG #PV #LV #SN Attr VSize VFree
PV VG Fmt Attr PSize PFree
/dev/vda3 vg_fedora3 vg_centos3 lvm2 a-- 914.51g 04.54g
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
lv_home vg_fedora3 vg_centos3 -wi-ao ---- 1.00g lv_root vg_fedora3 vg_centos3 -wi-ao ---- 8.00g lv_swap vg_fedora3 vg_centos3 -wi-ao 520---- 992.00m
* '''f17host c6host (i.e. "removable hard disk" or "disk pack")'''
Does not use LVM. Confirm this using the same commands used above.
