Questions tagged [lvm]

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.

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195
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6answers
76k 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 ...
20
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4answers
52k 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 ...
10
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8answers
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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: ...
6
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6answers
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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? ...
29
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3answers
23k 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 ...
9
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5answers
14k 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: ...
23
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11answers
36k 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 ...
17
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9answers
29k 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 ...
27
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7answers
51k 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 ...
20
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6answers
14k 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. ...
7
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4answers
22k 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 /dev/vg_dev/...
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3answers
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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) ...
6
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2answers
6k 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 ...
23
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6answers
28k views

Does LVM need a partition table?

It appears that I am able to successfully do a pvcreate on top of a raw block device, without ever taking the step of creating a partition table. I am then able to create a volume group, logical ...
12
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5answers
32k views

How to recover logical volume deleted with lvremove

I am on CentOS 5.5 and am running Xen. I have a large volume group that I create logical volumes on using lvcreate. Today I had a customer cancel her account, then change her mind about an hour ...
16
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7answers
168k views

How to extend a Linux PV partition online after virtual disk growth

VMware allows to extend the size of a virtual disk online - when the VM is running. The next expected steps for Linux system are: extend the partition: delete and create a larger one with fdisk ...
17
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6answers
25k views

Commit or revert a Linux LVM snapshot?

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 ...
19
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7answers
19k 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
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9answers
60k views

Logical volumes are inactive at boot time

I resized my logical volume and filesystem and all went smoothly. I installed new kernel and after reboot I can't boot neither current nor former one. I get volume group not found error after ...
17
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7answers
22k 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 ...
28
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5answers
25k 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 ...
14
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3answers
4k views

Linux device-mapper maps LVM PV nested inside LV when taking snapshot

Which is really messing with my plan to back up this machine... I have a server which is a KVM hypervisor to several virtual machines. One of these is running Docker. It has its Docker volumes on /...
14
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4answers
7k 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 ...
6
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1answer
9k views

Advantages and disadvantages of Logical Volume Manager (LVM)? And LVM vs encrypted LVM?

In my situation, it's for a local build/staging server running ubuntu server. Things I'd like to know are: Why I should/shouldn't use LVM? What problems might it cause in terms of either regular ...
5
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2answers
5k 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 ...
2
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1answer
1k views

Recovering Accidentally Destroyed LVM2 Information

Ok, so I'm stupid and made a serious and grave mistake. On my linux box running Ubuntu 10.10, I have a 1.5TB RAID array that I had originally setup using the instructions located here: http://www....
7
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2answers
7k views

Insufficient suitable allocatable extents when extending lvm

I have a volume-group (vg) with about 127GB free space. I am trying to extend a logical volume to +50GB however i am getting insufficient suitable allocatable extents This is quite weird since ...
3
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1answer
2k views

pvcreate not working: can't open exclusively

After having added 2 disks of 1Tb to a Dell PowerEdge, I went through their initialization with the goal to add them to an existing LVM VG. When the MegaCli background initialization went complete, I ...
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3answers
27k views

How to change Volumegroup PE size

I am trying to increase the PE size of one of my Volume groups. I mistakenly set it as 4M to start when it should have been 32M . When I try to change the size I get vgchange -s 32M the_vol New ...
5
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3answers
5k views

Which scheduler to change on LVM to benefit virtual machines

When you have LVM, you have an entry for a scheduler in /sys/block for your physical volumes, but also for each individual logical volume, and the raw device. We have a Debian 6 LTS x64, kernel 2.6....
2
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3answers
4k 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% / ...
0
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2answers
460 views

Kill a process inside an lvm snapshot

In my XEN host, I have a snapshot that cannot be removed with lvremove $ lvremove /dev/vg0/snap-tmp-vm06.docker-disk -fdv DEGRADED MODE. Incomplete RAID LVs will be processed. Using logical volume(s) ...
23
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4answers
34k 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 ...
47
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6answers
53k views

What is better LVM on RAID or RAID on LVM?

I currently have LVM on software RAID, but I'd like to ask you what you think it is better solution, maybe some pros and cons? Edit: It is about software raid on lvm or lvm on software raid. I know ...
22
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6answers
25k 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 ...
50
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3answers
65k views

Is it possible to on-line shrink a EXT4 volume with LVM?

Today I tried this on my machine with OpenSUSE 12.3 (kernel 3.7): # resize2fs /dev/mapper/system-srv 2G resize2fs 1.42.6 (21-Sep-2012) Filesystem at /dev/mapper/system-srv is mounted on /srv; on-line ...
28
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1answer
6k 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) ...
33
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4answers
14k 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 ...
15
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1answer
13k views

Resizing a LUKS encrypted volume

I have a 500GiB ext4 filesystem on top of LUKS on top of an LVM LV. I want to resize the LV to 100GiB. I know how to resize ext4 on top of an LVM LV, but how do I deal with the LUKS volume? mgorven@...
12
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3answers
8k 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 ...
15
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5answers
25k views

Is online disk resize possible with KVM?

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 ...
13
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5answers
11k 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 ...
10
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5answers
20k views

Best practices for thin-provisioning Linux servers (on VMware)

I have a setup of about 20 Linux machines, each with about 30-150 gigabytes of customer data. Probably the size of data will grow significantly faster on some machines than others. These are virtual ...
8
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4answers
5k 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, ...
8
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2answers
5k 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 ...
5
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3answers
14k 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 ...
8
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3answers
14k views

debian 6 preseeding keeps asking “Write the changes to disks and configure LVM?”

I try to use an expert recipe configuring lvm for debian 6.0.5 netinstall. I don't want to be asked any questions, but it keeps asking me "Write the changes to disks and configure LVM?" Here is part ...
6
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4answers
6k views

Linux Software RAID1: How to boot after (physically) removing /dev/sda? (LVM, mdadm, Grub2)

A server set up with Debian 6.0/squeeze. During the squeeze installation, I configured the two 500GB SATA disks (/dev/sda and /dev/sdb) as a RAID1 (managed with mdadm). The RAID keeps a 500 GB LVM ...
5
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6answers
4k 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 ...
4
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2answers
7k views

repair partition table

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 over the ...