vgextend my-lv /dev/sdb
Device /dev/sdb excluded by a filter.
wipefs -a /dev/sdb
/dev/sdb: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 8 bytes were erased at offset 0x77ffffe00 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
vgextend my-lv /dev/sdb
Physical volume “/dev/sdb” successfully created.
Volume group “my-lv” successfully extended
Make sure you backups and make sure uuid is correct:
ls -l /etc/lvm/archive/
cat less /etc/lvm/archive/vg_test.vg
physical_volumes {
pv0 {
id = “gT7Kw0-bVoF-8reX-QVYs-9bvh-PMdo-bU5Vzo”
pvcreate –uuid “gT7Kw0-bVoF-8reX-QVYs-9bvh-PMdo-bU5Vzo” \
–restorefile /etc/lvm/archive/vg_test.vg
vgcfgrestore -f /etc/lvm/archive/vg_test.vg vg_test
vgchange -ay vg_test
lvs -o+cache_mode,cache_settings /dev/centos/data
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert CacheMode CacheSettings
data centos Cwi-aoC— <2.54t [lv_cache] [data_corig] 3.16 0.09 0.00 writethrough
lvchange –cachemode writeback centos/data
Logical volume centos/data changed
lvs -o+cache_mode,cache_settings /dev/centos/data
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert CacheMode CacheSettings
data centos Cwi-aoC— <2.54t [lv_cache] [data_corig] 3.72 0.09 0.00 writeback
lvdisplay /dev/lvm-group/lv-name | grep Size
LV Size 60.00 GiB
take 10-20% of this space:
lvcreate –size 7G –snapshot –name lv-name-snap /dev/lvm-group/lv-name
copy and compress:
dd if=/dev/lvm-group/lv-name-snap | gzip -1 - | ssh [email protected] dd of=/backups/lvm-images/lv-name-snap.gz
from backup server:
ssh user@remote "dd if=/dev/lvm-group/lv-name-snap | gzip -1 -" | dd of=/backups/lvm-images/lv-name-snap.gz
remove snapshot image:
lvremove /dev/lvm-group/lv-name-snap
Please be carefully with dd command, this command can be destructive.
mounting lvm nested partitons
lvdisplay /dev/kvm-group/vsv1098-0bzd-kujg5vyyvoa5sqyk
fdisk -l /dev/kvm-group/vsv1098-0bzd-kujg5vyyvoa5sqyk
kpartx -a /dev/kvm-group/vsv1098-0bzd-kujg5vyyvoa5sqyk
mkdir /mnt/vsv1098-0bzd-kujg5vyyvoa5sqyk1 && mount /dev/kvm-group/vsv1098-0bzd-kujg5vyyvoa5sqyk1 /mnt/vsv1098-0bzd-kujg5vyyvoa5sqyk1
ls /mnt/vsv1098-0bzd-kujg5vyyvoa5sqyk1
The cache logical volume type uses a small and fast LV to improve the performance of a large and slow LV. It does this by storing the frequently used blocks on the faster LV. LVM refers to the small fast LV as a cache pool LV. The large slow LV is called the origin LV. Due to requirements from dm-cache (the kernel driver), LVM further splits the cache pool LV into two devices – the cache data LV and cache metadata LV. The cache data LV is where copies of data blocks are kept from the origin LV to crease speed. The cache metadata LV holds the accounting information that specifies where data blocks are stored (e.g. on the origin LV or on the cache data LV). Users should be familiar with these LVs if they wish to create the best and most robust cached logical volumes. All of these associated LVs must be in the same VG.
lvs
/dev/vm_backups/backup read failed after 0 of 4096 at 995903864832: Input/output error
/dev/vm_backups/backup read failed after 0 of 4096 at 995903922176: Input/output error
/dev/vm_backups/backup read failed after 0 of 4096 at 0: Input/output error
/dev/vm_backups/backup read failed after 0 of 4096 at 4096: Input/output error
dmsetup remove vm_backups-backup
or:
vgreduce –removemissing
vgchange --refreshLVM advantages:
LVM disadvantages:
I recommend use LVM, because of great power.
lvextend -L100G /dev/volume_group/logical_volume
lvextend -L+10G /dev/volume_group/logical_volume
lvextend -l +100%FREE /dev/volume_group/logical_volume (this command isn’t very safe)
You can face this problem after trying to resize your logical volume partitions:
lvresize -L +2G /dev/mapper/VolGroup-lv_root
Extending logical volume lv_root to 10.07 GiB
device-mapper: resume ioctl on failed: Invalid argument
Unable to resume VolGroup-lv_root (253:0)
Problem reactivating lv_root
you can fix this booted from rescue image:
fdisk /dev/vda d 2 n 2 old_start new_end t 2 8e (Linux LVM) w then: lvextend -l +100%FREE /dev/VolGroup/lv_root lvmdiskscan
vgchange -aypvresize –setphysicalvolumesize 15G /dev/vda
pvs -v –segments /dev/vda2
Using physical volume(s) on command line
PV VG Fmt Attr PSize PFree Start SSize LV Start Type PE Ranges
/dev/vda2 VolGroup lvm2 a– 9.51g 0 0 2066 lv_root 0 linear /dev/vda2:0-2065
/dev/vda2 VolGroup lvm2 a– 9.51g 0 2066 368 lv_swap 0 linear /dev/vda2:2066-2433
LVM is a tool for logical volume management which includes allocating disks, striping, mirroring and resizing logical volumes.
With LVM, a hard drive or set of hard drives is allocated to one or more physical volumes. LVM physical volumes can be placed on other block devices which might span two or more disks.
The physical volumes are combined into logical volumes, with the exception of the /boot/ partition. The /boot/ partition cannot be on a logical volume group because the boot loader cannot read it. If the root (/) partition is on a logical volume, create a separate /boot/ partition which is not a part of a volume group.
Since a physical volume cannot span over multiple drives, to span over more than one drive, create one or more physical volumes per drive.
The volume groups can be divided into logical volumes, which are assigned mount points, such as /home and / and file system types, such as ext2 or ext3. When “partitions” reach their full capacity, free space from the volume group can be added to the logical volume to increase the size of the partition. When a new hard drive is added to the system, it can be added to the volume group, and partitions that are logical volumes can be increased in size.
Read more http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-lvm.html