Unix and Linux Stack Exchange
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Questions tagged [lvm]

Logical Volume Management provides storage abstraction, a generalization of disk partitioning.

LVM is a collection of user-space utilities and kernel modules that provide layers of abstraction to the storage available on Unix systems. Among its many notable features are the ability to:

  • combine many disks into one storage pool
  • stripe volumes across different physical storage devices
  • mirror volumes
  • snapshot volumes
  • enlarge or shrink volumes, often without system downtime
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How to shrink root filesystem without booting a livecd

I find myself needing to rearrange a system's partitions to move data previously under the root filesystem into dedicated mount points. The volumes are all in LVM, so this is relatively easy: create new volumes, move data into them, shrink the root…
Tom Hunt
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Does LVM impact performance?

I have to migrate a few servers to Linux, and one important aspect that I need to evaluate is that my new host system must have elastic storage capacity. Naturally, doing some basic research, I came across LVM. Is there any performance penalty for…
Pablo
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SSH to decrypt encrypted LVM during headless server boot?

When I installed Ubuntu 10.04 and, now, 10.10, I was offered the option of enabling "encrypted LVM" for my hard drive. After choosing that option, I am prompted for my password during boot to decrypt the LVM. Now, I am thinking about setting up a…
hpy
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RAIDing with LVM vs MDRAID - pros and cons?

In his answer to the question "mixed raid types", HBruijn suggests using LVM to implement RAID vs the more standard MDRAID. After a little investigation, it seems LVM also supports RAID functionality. In the past, I have used LVM on top of MDRAID,…
Faheem Mitha
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Should LVM partitions be used in virtual machine images?

Should LVM be used for the partitions when creating VM images (e.g., KVM images)? It seems like it adds complexity if you want to, say, mount a qcow2 image in the host if the image has LVM partitions. On the other hand, it doesn't seem like the…
Lorin Hochstein
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The merits of a partitionless filesystem

I ran into something a couple of weeks ago that I'd never seen before: A filesystem (ext3 I believe) installed to a storage device without a partition. In essence /dev/sdb was the entire filesystem. I know many filesystems can be extended into empty…
sysadmin1138
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How do I extend a partition with a LVM and the contained physical volume and logical volume?

On my 240 GB SSD I had at first two partitions, one containing the Logical Volume with Linux Mint and the other had contained a NTFS partition to share with Windows. Now I removed the NTFS partition and want to extend my logical volume group to use…
klingt.net
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How to reduce Volume Group size in LVM?

[root@localhost ~] vgdisplay --- Volume group --- VG Name vg_root System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 7 VG Access read/write VG Status …
gasko peter
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/dev/mapper in fdisk

After installing CentOS, I see several lines like /dev/mapper/centos_jackpc--11-swap and /dev/mapper/centos_jackpc--11-root when I issue fdisk -l. What is the purpose of these? And why do they not show up for Ubuntu? The full fdisk -l is shown…
Tosh
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Swap partition in LVM?

I was wondering if putting the swap partition into a logical volume group has any drawbacks (e.g. performance), or would it be "just the same" as having it as a separate primary/logical partition? I like the fact that it could be easily resized if…
Levite
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What is lvmetad and why would I want or need to use it?

I have a Gentoo server with LVM running on top of a RAID array that I have been using for a number of years. Recently I upgraded LVM to 2.02.109 (don't recall what version it was before) and received a message while upgrading: * Make sure to enable…
Steve Kalemkiewicz
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snap /dev/loop at 100% utilization -- no free space

Free space: thufir@dur:~$ thufir@dur:~$ df -h Filesystem Size Used Avail Use% Mounted on udev 3.9G 0 3.9G 0% /dev tmpfs 794M 9.8M 785M 2% /run /dev/mapper/ubuntu--vg-root …
Thufir
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Using LVM with SSD and SATA drives

I saw in this question that it is possible to place both a SSD and a standard SATA hard drive into a single LVM volume group (VG). How does this affect performance? Is there a way to force the OS to be on the SSD while the data is on the SATA…
Nick
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lvm devices under /dev/mapper missing

I'm using Debian squeeze, and running LVM on top of software RAID 1. I just accidentally just discovered that most of the links under /dev/mapper are missing, though my system seems to be still functioning correctly. I'm not sure what happened. The…
Faheem Mitha
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What is the best practice for adding disks in LVM

According to the Linux manpages you can add raw disks as well as partitions to a volume group. In other documentation (RedHat, CentOS or openSUSE), all examples refer to adding partitions to the VG instead of raw disks. What is common (best)…
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