In computer storage, Logical Volume Management or LVM provides a method of allocating space on mass-storage devices that is more flexible than conventional partitioning schemes.

learn more… | top users | synonyms (1)

116
votes
5answers
34k views

LVM dangers and caveats

I have recently started using LVM on some servers for hard drives larger than 1 TB. They're useful, expandable and quite easy to install. However, I could not find any data about the dangers and ...
16
votes
5answers
11k views

Possible to get SSD TRIM (discard) working on ext4 + LVM + software RAID in Linux?

We use RAID1+0 with md on Linux (currently 2.6.37) to create an md device, then use LVM to provide volume management on top of the device, and then use ext4 as our filesystem on the LVM volume groups. ...
19
votes
2answers
6k views

Readahead Settings for LVM, Device-Mapper, Software Raid and Block Devices - what wins?

I've been trying to find a straight answer on this one, and it has proved elusive. This question and its answer is close, but does not really give me the specifics I would like. Let's start with ...
5
votes
5answers
5k views

LVM mirroring VS RAID1

Having learned a bit about LVM mirroring, I thought about replacing the current RAID-1 scheme I'm using to gain some flexibility. Problem is that according to what I found on the Internet, LVM is: ...
5
votes
6answers
5k views

Is there a way to do something like LVM over NFS?

I realize that since NFS is not block-level, LVM can't be used directly. However: is there a way to combine multiple NFS exports (from, say, 3 servers) into one mount point on a different server? ...
15
votes
9answers
19k views

LVM snapshots as a backup strategy

How viable as a backup strategy would be periodical LVM snapshots of xen domU's? Pros, cons, any gotchas? To me it seems like the perfect solution for a fast, brainless restore. Any investigation ...
11
votes
3answers
10k views

How to resize root LVM partition in Fedora without LiveCD or Rebooting

I have a virtual machine that recently had its disk image increased from 20GB to 50GB, and fdisk -l verifies that the VM can see this new size. Now I need to resize my root LVM partition to fill the ...
12
votes
4answers
23k views

Is this how LVM snapshots work?

I'm trying to figure out how LVM snapshots work so I can implement it on my fileserver but I'm having difficulty finding anything on google that explains how it works instead of how to use it for a ...
14
votes
7answers
10k views

Is it possible to convert a Linux box to LVM after the fact?

My Linux server uses LVM because I replace the machine a year ago and installed from scratch. LVM has been a life saver and I love its flexibility. My Linux laptop, however, was last fully installed ...
10
votes
5answers
13k views

How do I easily repair a single unreadable block on a Linux disk?

My Linux system has started throwing SMART errors in the syslog. I tracked it down and believe the problem is a single block on the disk. How do I go about easily getting the disk to reallocate that ...
9
votes
8answers
18k views

Ubuntu: Resize the root LVM(2?) partition

I have an Ubuntu virtual machine running in VirtualBox 2.2.4, and I created it on an 8gb virtual disk which is too small. So, I am trying to increase the size of the disk. So far, I have done this: ...
5
votes
2answers
2k views

Ubuntu Kickstart installation using LVM waits for input

I have a PXE Boot Setup for installing CentOS 5 and Ubuntu 10.04 via Kickstart. I use LVM and installing CentOS without any user interaction works but Ubuntu always asks to "confirm to write changes ...
1
vote
3answers
2k views

Centos Xen resizing DomU partition and volume group

I have a setup like so: Dom0 LV | DomU Physical Disk | | XVDA1 XVDA2 (/boot) (DomU PV) | VolGroup00 (DomU VG) ...
3
votes
1answer
657 views

Change a non-striped LVM LV into a striped LV

I currently have several logical volumes (LVs) on a volume group (VG). This VG is hosted on a single physical volume (PV). I have a spare drive which I can use to shuffle data around on. I also now ...
1
vote
1answer
125 views

Can LVM and Traditional Partitions Coexist?

Can you set up a machine in which different drives are formatted as either LVM volumes or as traditional partitions and mix and match the two? For e.g. have the LVM volume mounted as / and /home and ...
8
votes
3answers
5k views

LVM Performance overhead?

I would be thankfull if someone who understands how LVM works, could tell me a rough estimate, how much slower using LVM (with a Software RAID1) will be. (What I do not want to know how much slower ...
2
votes
3answers
212 views

Repartitioning already mounted logical volumes

This is my current disk state on a physical CentOS machine: Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_ecomwise-lv_root 50G 47G 267M 100% / tmpfs ...
2
votes
1answer
150 views

Do I need to enable LVM at install time?

I'm setting up a CentOS dedicated server and I would like to use LVM (it's the right thing to do, isn't it?) The thing is, I'm not sure if I have an option to enable LVM at the time of installation. ...
1
vote
3answers
717 views

Increase Linux Partition dynamically?

Here is what I have on my Linux Box [root@linxuph53 logs]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_linuxph53-lv_root 38G 11G 26G 29% / ...
13
votes
9answers
19k views

Sync LVM snapshots to backup server

I have a number of Xen virtual machines running on a number of Linux servers. These VMs store their disk images in Linux LVM volumes with device names along the lines of /dev/xenVG/SERVER001OS and so ...
24
votes
1answer
3k views

When using software RAID and LVM on Linux, which IO scheduler and readahead settings are honored?

In the case of multiple layers (physical drives -> md -> dm -> lvm), how do the schedulers, readahead settings, and other disk settings interact? Imagine you have several disks (/dev/sda - /dev/sdd) ...
21
votes
4answers
4k views

LVM snapshots vs. file system snapshots

As far as I know, LVM makes it possible to take snapshots of a volume. There are also a number of file systems (ZFS, Btrfs, reiserfs, ...) which supports snapshots. However, I've never understood the ...
11
votes
4answers
6k views

KVM/qemu - use LVM volumes directly without image file?

I'm not quite sure how to phrase this question (hence the poor title), so let me provide an example of what I'm trying to do. On my (old) Xen host, I'm able to present LVM filesystems directly to ...
9
votes
5answers
11k views

Linux LVM snapshot commit or revert?

I'm about to perform an experimental upgrade on my CentOS 5 server. If the upgrade fails, I want to be able to back out the changes to the filesystem. This scenario seems similar to the example in ...
8
votes
4answers
3k views

Using 4k drives with md/LVM/dm-crypt

I know that I have to align my 4k drives by a multiple of 8 sectors, but what about md-RAID / LVM / dm-crypt? How do I tell these layers that my drive is 4k? If they don't respect the 4k sector size, ...
14
votes
4answers
5k views

Improving IO with FlashCache

I have a server with 2 HDD's (2x 1 TB), running in RAID 1 (SW-RAID). I want to improve IO performance by using flashcache. There are running KVM virtual machines on it, using LVM. Regarding this, I ...
9
votes
5answers
4k views

LVM and disaster recovery

I understand what LVM is and what it accomplishes, but I feel like I am missing some things. Lets say we have two physical drives, sda and sdb. Both are 100 Megs. I put them into VolumeGroup1 and ...
8
votes
3answers
6k views

LVM volume group shared between KVM/libvirt host and guests: is this a bad idea?

I have just built a shiny new KVM/libvirt-based virtual machine host, containing 4 SATA II hard drives, and running CentOS 5.5 x86_64. I have decided to create virtual machine disks as logical ...
5
votes
1answer
4k views

HP DL380 G7 + Smart Array P410i + sysbench -> poor raid 10 performance

I have running system with low IO utilization: HP DL380G7 ( 24gb RAM ) Smart Array p410i with 512mb battary backed write cache 6x SAS 10k rpm 146gb drives in RAID10 Debian Squeze linux, ext4 + LVM, ...
5
votes
5answers
1k views

Need help with recovering RAID array

To make a long story short, I am responsible for a media server that has two RAID arrays (/dev/md0 and /dev/md2). I still have a ton to learn about software RAID and LVM, etc. We had a drive fail in ...
4
votes
1answer
3k views

LVM logical volume partition corrupted after lvreduce

I encounter the problem when I try to shrink one logical volume. I took the actions as following steps shows: # unmount /home # lvreduce --size -100G /dev/vg_dev/lv_home # lvdisplay ...
4
votes
2answers
4k views

repair partition table

Hallo. I've just overwritten my partition table of my system's hard disk. i made a cfdisk on the wrong device (/dev/sda instead of /dev/sdd), deleted all partitions, made one new primary spanning ...
4
votes
6answers
3k views

JFS or XFS or anything else?

After deciding to use LVM2 as volumemanager on our servers there was also the wish for an online resizeable filesystem. After reading a few articles I decided to use JFS in favour of XFS. Now today I ...
1
vote
1answer
3k views

Adding Virtio block devices at runtime in Libvirt KVM

I'm running Debian Wheezy Beta 4 with KVM based guest systems which run the same operating system. I'm using LibVirt to manage the virtualisation. What I would like to do is to attach an LVM based ...
1
vote
3answers
3k views

KVM booting off-image kernel and existing partition

I am in the process of switching from Xen to qemu-kvm. My current Xen installation has a number of LVM volumes each with a partition (rather than a full disk image). In Xen, I start each VM with a ...
1
vote
2answers
6k views

Cannot deactivate LV due to partition device

I need to be able to deactivate an LV but cannot after partprobing it and finding gaining access to its partitions in /dev/mapper. It seems I need some way of 'un-partprobing' the disk, but I have no ...
5
votes
7answers
5k views

Do you lose everything when you have a hard disk failure in a multi-hard disk LVM that does NOT use RAID?

I'm debating about using LVM for a media/file server because I would like to combine multiple physical hard disks into one volume. I do not wish to use any RAID in my LVM so my question is: If one ...
5
votes
2answers
3k views

Should I be using LVM snapshots along with rsnapshot?

I manage a CentOS 4.8 server for a small workgroup. Last year I converted the filesystem to LVM over software RAID (RAID 1, two mirrored drives). I now have the following filesystems on LVM/RAID: ...
4
votes
1answer
375 views

3 drives fell out of Raid6 mdadm - rebuilding?

i had an mdadm raid6 array with 13x1TB drives. Within 10 minutes 3 of these drives fell out of the array... we assume bad cable to the controller card and replaced, however now we need to get the ...
4
votes
2answers
7k views

LVM -> dd -> LVM?

I've 'cloned' a LVM partition using dd over ssh to a remote server(emergency backup...). On that remote server, is it possible to 'transform' the dd cloned file back into a LVM partition? Thanks. ...
3
votes
2answers
913 views

Is the fdisk partition type important when using lvm

I have inherited a few LVM volumes and I noticed that fdisk reports the disks that make up the volume group as partition type 83 (Linux) and not 8e (Linux LVM). Is this a problem and how important ...
3
votes
2answers
2k views

Cannot recover from failed RAID

My situation is different from this one. I have a CentOS system with 3 hard drives, and the following software RAID arrays: /boot on RAID 1 over 2 disks / on RAID 5 over 3 disks swap on RAID 0 over ...
1
vote
3answers
101 views

Long running VMWare snapshots are bad… but what about VMDKs on a ZFS\LVM snapshot?

The VMWare KB and multiple blogs state that long running snapshots are bad for both performance reasons and integrity. They have valid points. Granted this is not with ESXi but rather ...
0
votes
4answers
3k views

Linux LVM: Single or Multiple Harddisk Partitions?

I am about to add a second harddisk to my server for data storage and have decided to use LVM. My plan is to use one volume group with server logical volumes. Since the disk is new I need to partition ...
5
votes
2answers
2k views

Is it possible to convert striped logical volume to linear logical volume?

I've a logical volume that is striped across three physical volumes. I had to move this logical volume to another physical volume. This worked nicely with pvmove command. However, I discovered later ...
4
votes
5answers
8k views

KVM online disk resize?

We're evaluting KVM for Linux virtualization on a few projects. All is going well so far. But one of our requirements is the ability to add disk space to a running guest without rebooting or taking it ...
3
votes
3answers
1k views

Slow disk I/O in KVM with LVM and md raid5

I have been battling with a kvm setup under debian for two weeks now, specifically with guest I/O disk performance. The system: -Supermicro 1018d-73mtf (X10SL7-F motherboard) -16GB ECC/UB -Intel ...
3
votes
1answer
8k views

How to copy KVM disk image to LVM

Problem I'm getting a No space left on device error when doing a dd command. I'm trying to move a KVM qcow2 file to an LVM partition and thought that the LVM partition needed to be the same size as ...
2
votes
1answer
219 views

What kind of “volume/storage management” has the largest support/feature set these days? [closed]

(DISCLAIMER: This is "time bound" as probably every other question, I just point it out now instead of implicating it) part of reviewing a few basic decisions for our infrastructure is once again the ...
2
votes
1answer
2k views

Grub2 reports physical volume pv0 not found when probing/installing

I upgraded a Ubuntu Maverick to Precise server but I get the following error while updating grub: error: physical volume pv0 not found. Now, for my system I have /dev/sda through /dev/sde ...