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Use "LVS" command to list the available LOGICAL VOLUMES on the SYSTEM.

Use "lvs" command to list the available logical volumes on the system.

Use "PVS" COMMAND to list the available PHYSICAL volumes.

Use "pvs" command to list the available physical volumes.

USE "vgdisplay vg_name"

Use "vgdisplay vg_name"

USE "lvdisplay /dev/vg_name/lv_name"

Use "lvdisplay /dev/vg_name/lv_name"

USE "pvdisplay /dev/disk_name" EX: pvdisplay /dev/sde

Use "pvdisplay /dev/disk_name" Ex: pvdisplay /dev/sde

YES. Its possible to RENAME the volume group on fly. But the MOUNTED volumes will not reflect the same unless you re-mount the volume with NEW VG name. Need to update the /etc/fstab with new VG name to mount the volumes ACROSS the system reboot.

Yes. Its possible to rename the volume group on fly. But the mounted volumes will not reflect the same unless you re-mount the volume with new VG name. Need to update the /etc/fstab with new VG name to mount the volumes across the system reboot.

Use "vgcfgbackup vg_name" to TAKE the LATEST configuration BACKUP of volume group. The DEFAULT volume group backup location is "/etc/lvm/backup" .

Use "vgcfgbackup vg_name" to take the latest configuration backup of volume group. The default volume group backup location is "/etc/lvm/backup" .

RUN "vgmknodes" to RECREATE the LVM DEVICES FILES.

Run "vgmknodes" to recreate the LVM devices files.

"LVMDUMP" is tool for LVM2 to collect the various information for diagnostic purposes.By DEFAULT, it CREATES a tarball suitable for submission along with a problem report

"lvmdump" is tool for LVM2 to collect the various information for diagnostic purposes.By default, it creates a tarball suitable for submission along with a problem report

LVM1 SNAPSHOTS are READONLY by DEFAULT where LVM2 snapshots were read/write.

LVM1 snapshots are readonly by default where LVM2 snapshots were read/write.

1. CREATE a physical volume USING pvcreate command: #pvcreate /dev/sdc
2. Create a volume group using "vgcreate" command: #vgcreate vg02 /dev/sdc
3. Create a LOGICAL volume using "lvcreate" command: #lvcreate -L 100M -n vol1 vg02
4. Create a FILESYSTEM on logical volume using mkfs command: #mkfs -t ext4 /dev/vg02/vol1
5. MOUNT the filesystem using mount command for use: #mount -t ext4 /dev/vg02/vol1 /vol1

USING "vgextend" we can INCREASE the VOLUME GROUP.

Using "vgextend" we can increase the volume group.

1. Get the 50GB LUN from STORAGE TEAM.(/dev/sdd)
2. Create physcical volume ( # pvcreate /dev/sdd )
3. Extend the volume group (# vgextend vg02 /dev/sdd)

"vgreduce VG02 /dev/sdd/"

"vgreduce vg02 /dev/sdd/"

• Un-mount all the logical filesystems
• Remove the logical volumes using "lvremove" command.
• DESTROY the VOLUME group using "vgremove" command.
• Use "pvremove" command remove the PHYSICAL volumes from the SYSTEM.

Using fdisk utility we can create partitions from the RAW disk.Below are the steps to create partition from the raw disk :

• fdisk /dev/hd* (IDE) or /dev/sd* (SCSI)
• TYPE n to create a new partition
• After creating partition , type W command to WRITE the changes to the partition table.

Using fdisk utility we can create partitions from the raw disk.Below are the steps to create partition from the raw disk :

LVM stands for Logical Volume Manager , to RESIZE filesystem's size online we required LVM partition in Linux. Size of LVM partition can be extended and reduced USING the lvextend & lvreduce COMMANDS respectively.

LVM stands for Logical Volume Manager , to resize filesystem's size online we required LVM partition in Linux. Size of LVM partition can be extended and reduced using the lvextend & lvreduce commands respectively.

Below are the Logical STEPS :

­ Use the lvextend command (lvextend ­L +100M /DEV/<Name of the LVM Partition> , in this example we are extending the SIZE by 100MB. 
­ resize2fs /dev/<Name of the LVM Partition>
­ check the size of partition USING ‘df ­h’ command

Below are the Logical Steps :

­ Use the lvextend command (lvextend ­L +100M /dev/<Name of the LVM Partition> , in this example we are extending the size by 100MB. 
­ resize2fs /dev/<Name of the LVM Partition>
­ check the size of partition using ‘df ­h’ command

Below are the logical Steps to reduce size of LVM partition :

­Umount the FILESYSTEM using umount command, ­USE resize2fs command ,
e.g resiz2fs /dev/mapper/myvg­mylv 10G ­Now use the lvreduce command ,
e.g lvreduce ­L 10G /dev/mapper/myvgmylv 

Above Command will shrink the size & will make the filesystem size 10GB.

Below are the logical Steps to reduce size of LVM partition :

­Umount the filesystem using umount command, ­use resize2fs command ,
e.g resiz2fs /dev/mapper/myvg­mylv 10G ­Now use the lvreduce command ,
e.g lvreduce ­L 10G /dev/mapper/myvgmylv 

Above Command will shrink the size & will make the filesystem size 10GB.

Sar Collect, report, or save system activity information. The default version of the sar command (CPU utilization report) might be one of the FIRST facilities the user runs to begin system activity INVESTIGATION, because it monitors major system resources. If CPU utilization is near 100 PERCENT (user + nice + system), the workload SAMPLED is CPU­bound. 

By default log files of Sar command is located at /var/log/sa/sadd file, where the dd parameter indicates the current day.

Sar Collect, report, or save system activity information. The default version of the sar command (CPU utilization report) might be one of the first facilities the user runs to begin system activity investigation, because it monitors major system resources. If CPU utilization is near 100 percent (user + nice + system), the workload sampled is CPU­bound. 

By default log files of Sar command is located at /var/log/sa/sadd file, where the dd parameter indicates the current day.

Using fdisk utility we can create partitions from the RAW disk.Below are the steps to create partition from the raw dsik :

• fdisk /dev/hd* (IDE) or /dev/sd* (SCSI)
• Type N to create a new partition 
• After creating partition , type W command to write the CHANGES to the partition table.

Using fdisk utility we can create partitions from the raw disk.Below are the steps to create partition from the raw dsik :

Use "VGS" COMMAND to DISPLAY the imported VOLUME group.

Use "vgs" command to display the imported volume group.

• EXTEND the logical volume
• Increase the Filesystem size
• Verify the STATUS using df COMMAND or lvs command.

USE "LVS -a -o +DEVICES"

use "lvs -a -o +devices"

"vgchange -AY volume_group_name" .

"vgchange -ay volume_group_name" .

"vgchange -an volume_group_name".

"vgchange -an volume_group_name".

"lvchange -AY /dev/vg_name/lv_name".

"lvchange -ay /dev/vg_name/lv_name".

"lvchange -an /dev/vg_name/lv_name"

"lvchange -an /dev/vg_name/lv_name"

lvscan

lvscan

Use "vgscan" to SCAN EXISTING volume GROUP from newly connected SAN or DISKS.
But we should use "pvscan" prior to EXECUTING this command.

Use "vgscan" to scan existing volume group from newly connected SAN or DISKS.
But we should use "pvscan" prior to executing this command.

Use "echo 1 &GT; /sys/class/scsi_host/hostx/scan" to scan DISK from newly connected SAN or DISKS and also replace the "x" with NUMBER of HOST ID present under /sys/class/scsi_host/.

Use "echo 1 > /sys/class/scsi_host/hostx/scan" to scan disk from newly connected SAN or DISKS and also replace the "x" with number of host id present under /sys/class/scsi_host/.

No. we can't REDUCE the logical volume on fly. Here is the steps to reduce the logical volume.

• Un-MOUNT the FILESYSTEM
• Run e2fsck on the volume DEVICE
• Reduce the Filesystem using resize2fs
• Reduce the logical Volume using lvreduce
• Mount the filesystem back for production.

No. we can't reduce the logical volume on fly. Here is the steps to reduce the logical volume.

Yes. LVM has the FEATURE to increase the VOLUME without UNMOUNT it.

Yes. LVM has the feature to increase the volume without unmount it.

# vgcfgbackup /dev/vgname

# vgcfgbackup /dev/vgname

Syntax:

# vgreduce &LT;vgname&GT; <disk>
Example:
# vgreduce vgname /dev/sdb

Syntax:

# vgreduce <vgname> <disk>
Example:
# vgreduce vgname /dev/sdb

SUPPOSE DISK is /dev/sdb
# pvcreate /dev/sdb
# vgextend &LT;VGNAME&GT; /dev/sdb

suppose disk is /dev/sdb
# pvcreate /dev/sdb
# vgextend <vgname> /dev/sdb

SWAP (82), RAID (FD) and LVM (8e)

SWAP (82), RAID (fd) and LVM (8e)

# lvextend -SIZE +&LT;addsize&GT; /DEV/<vgname>/<lvname>

resize2fs /dev/<vgname>/<lvname>

# lvextend -size +<addsize> /dev/<vgname>/<lvname>

resize2fs /dev/<vgname>/<lvname>

# vgreduce VGNAME /dev/sda7

# vgreduce vgname /dev/sda7

Firstly, create Physical VOLUME (/dev/sdaX, where X is the PARTITION NUMBER) of size 4GB.
Now run following COMMAND: # vgextend VGNAME /dev/sdaX

Firstly, create Physical volume (/dev/sdaX, where X is the partition number) of size 4GB.
Now run following command: # vgextend vgname /dev/sdaX

For 2.4 based kernels, the MAXIMUM LV size is 2TB. For 32-bit CPUs on 2.6 kernels, the maximum LV size is 16TB. For 64-bit CPUs on 2.6 kernels, the maximum LV size is 8EB.

For 2.4 based kernels, the maximum LV size is 2TB. For 32-bit CPUs on 2.6 kernels, the maximum LV size is 16TB. For 64-bit CPUs on 2.6 kernels, the maximum LV size is 8EB.

In LVM2 SNAPSHOTS are READ/write by default, whereas in LVM1, snapshots were read only.

In LVM2 snapshots are read/write by default, whereas in LVM1, snapshots were read only.

Check the following file:

#CAT /proc/misc

if this file contains “device-mapper” TERM it MEANS device mapper is INSTALLED on your system.

Check the following file:

#cat /proc/misc

if this file contains “device-mapper” term it means device mapper is installed on your system.

LVM snapshots allow the administrator to create a new block device which PRESENTS an exact copy of a logical volume, FROZEN at some POINT in time.

LVM snapshots allow the administrator to create a new block device which presents an exact copy of a logical volume, frozen at some point in time.

A RAID DEVICE is a PHYSICAL grouping of disk devices in order to create a logical PRESENTATION of one device whereas LVM is a logical layer that that can be MANIPULATED in order to create and, or expand a logical presentation of a disk device to an OS.

A RAID device is a physical grouping of disk devices in order to create a logical presentation of one device whereas LVM is a logical layer that that can be manipulated in order to create and, or expand a logical presentation of a disk device to an OS.

LVM stands for Logical Volume MANAGER. LVM, is a storage management solution that allows administrators to divide hard drive space into PHYSICAL volumes (PV), which can then be combined into volume groups (VG), which are then DIVIDED into logical volumes (LV) on which the filesystem and mount point are created.

LVM stands for Logical Volume Manager. LVM, is a storage management solution that allows administrators to divide hard drive space into physical volumes (PV), which can then be combined into volume groups (VG), which are then divided into logical volumes (LV) on which the filesystem and mount point are created.