LVM - Revision history

Leaky: /* rescan the scsi bus */

2021-07-16T10:29:01Z

‎rescan the scsi bus

Leaky: /* rescan the scsi bus */

2021-07-16T10:28:42Z

‎rescan the scsi bus

Leaky at 20:59, 11 August 2020

2020-08-11T20:59:29Z

Leaky: /* Extending a filesystem to include a new partition */ added info about creating new LV

2019-09-27T08:18:41Z

‎Extending a filesystem to include a new partition: added info about creating new LV

Leaky: /* Extending a filesystem to include a new partition */

2015-10-07T11:09:43Z

‎Extending a filesystem to include a new partition

Leaky: /* Mounting a filesystem from a Xen disk file that has LVM on it */

2015-10-07T11:09:24Z

‎Mounting a filesystem from a Xen disk file that has LVM on it

Leaky: Created page with ' == Mounting a filesystem from a Xen disk file that has LVM on it == # losetup /dev/loop7 xenguest1.xvda.img # kpartx -v -a xenguest1.xvda.img If the disk partitions were jus…'

2013-09-21T19:28:58Z

Created page with ' == Mounting a filesystem from a Xen disk file that has LVM on it == # losetup /dev/loop7 xenguest1.xvda.img # kpartx -v -a xenguest1.xvda.img If the disk partitions were jus…'

New page

== Mounting a filesystem from a Xen disk file that has LVM on it ==

# losetup /dev/loop7 xenguest1.xvda.img
# kpartx -v -a xenguest1.xvda.img

If the disk partitions were just normal ones, you would be able to mount them now as /dev/loop7p1 /dev/loop7p2 etc. If the filesystems are contained within an LVM volume group there are some extra steps.

Scan physical volumes for LVM partitions

# pvscan
PV /dev/mapper/loop7p2 VG vg_xenguest1 lvm2 [29.51 GiB / 0 free]

Scan the partitions for volume groups

# vgscan
Reading all physical volumes. This may take a while...
Found volume group "vg_xenguest1" using metadata type lvm2

Scan for logical volumes. Any that are currently in use will show ACTIVE in the first column.

# lvscan
inactive '/dev/vg_xenguest1/lv_root' [28.54 GiB] inherit
inactive '/dev/vg_xenguest1/lv_swap' [992.00 MiB] inherit

Since these are inactive, they can't be used as devices (yet).

# lvdisplay /dev/vg_xenguest1/lv_root
...
LV Status NOT available
LV Size 28.54 GiB
...

First we need to set the volume group active, and then the logical volumes should work fine.

# vgchange -ay vg_xenguest1
2 logical volume(s) in volume group "vg_xenguest1" now active

And now we can mount the root filesystem.

# mkdir /mnt/xenguest1
# mount -t ext3 /dev/mapper/vg_xenguest1/lv_root /mnt/xenguest1

When you're finished with it, use the following commands to make the volumes inactive, remove the partitions from the kernel partition map and then remove the loopback device.

# vgchange -an vg_xenguest1
# kpartx -v -d /dev/loop7
# losetup -d /dev/loop7

@@ Line 11: / Line 11: @@
   # echo 1 > /sys/block/sda/device/rescan
-This should make it show the new size via
+This should make it show the new size via the command
-  fdisk -l /dev/sda
+  # fdisk -l /dev/sda
 == Creating new volumes ==

← Older revision		Revision as of 10:28, 16 July 2021
Line 6:		Line 6:

	It may not be host0 so check what's available. After this the new drive should show up.		It may not be host0 so check what's available. After this the new drive should show up.
		+
		+	If you simply increased the size of the existing disk, you can try:
		+
		+	# echo 1 > /sys/block/sda/device/rescan
		+
		+	This should make it show the new size via
		+
		+	fdisk -l /dev/sda

	== Creating new volumes ==		== Creating new volumes ==

← Older revision		Revision as of 20:59, 11 August 2020
Line 1:		Line 1:
		+	== rescan the scsi bus ==
		+
		+	If you've added another virtual disk to a VM, it may not see it without a reboot. If that's not going to be convenient it may show up by rescanning the scsi bus.
		+
		+	# echo "- - -" > /sys/class/scsi_host/host0/scan
		+
		+	It may not be host0 so check what's available. After this the new drive should show up.

	== Creating new volumes ==		== Creating new volumes ==

← Older revision		Revision as of 08:18, 27 September 2019
Line 1:		Line 1:
		+
		+	== Creating new volumes ==
		+
		+	Assuming that <code>/dev/sdb</code> is a new disk with a single full size partition <code>/dev/sdb1</code>, the following will create a new volume group called <code>data</code> and a couple of logical volumes inside called <code>projects</code> and <code>backups</code>
		+
		+	# pvcreate /dev/sdb1
		+
		+	# vgcreate data /dev/sdb1
		+
		+	# lvcreate -n projects -L 20G data
		+	# lvcreate -n backups -l 100%FREE data

	== Extending a filesystem to include a new partition ==		== Extending a filesystem to include a new partition ==

@@ Line 2: / Line 2: @@
 == Extending a filesystem to include a new partition ==
- '''IMPORTANT: Check the partitions, do not just copy/paste below!'''
+'''IMPORTANT: Check the partitions, do not just copy/paste below!'''
 Initialise the LVM metadata on the partition to add into the filesystem

← Older revision		Revision as of 11:09, 7 October 2015
Line 1:		Line 1:
		+
		+	== Extending a filesystem to include a new partition ==
		+
		+	'''IMPORTANT: Check the partitions, do not just copy/paste below!'''
		+
		+	Initialise the LVM metadata on the partition to add into the filesystem
		+
		+	# pvcreate /dev/sdb1
		+
		+	Add the partition to the volume group
		+
		+	# vgextend sys /dev/sdb1
		+	Volume group "sys" successfully extended
		+
		+	Extend the relevant logical volume to include all of the newly added space
		+
		+	# lvextend -l +100%FREE /dev/sys/root
		+	Size of logical volume sys/root changed from 27.88 GiB (892 extents) to 47.84 GiB (1531 extents).
		+	Logical volume root successfully resized
		+
		+	Resize the underlying filesystem to use the whole LVM device
		+
		+	# resize2fs /dev/sys/root
		+	resize2fs 1.41.12 (17-May-2010)
		+	Filesystem at /dev/sys/root is mounted on /; on-line resizing required
		+	old desc_blocks = 2, new_desc_blocks = 3
		+	Performing an on-line resize of /dev/sys/root to 12541952 (4k) blocks.
		+	The filesystem on /dev/sys/root is now 12541952 blocks long.

	== Mounting a filesystem from a Xen disk file that has LVM on it ==		== Mounting a filesystem from a Xen disk file that has LVM on it ==