Questions tagged [device-mapper]

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0answers
44 views

Is it possible to migrate between two physical disks without (much) downtime?

I have a server with a medium-sized database on a disk which is filling-up. There is no LVM or RAID or anything like that in play at this point. I already have the new disk installed in the server. Is ...
0
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0answers
44 views

DOCKER + daemon.json configuration

I need to configured the /etc/docker/daemon.json on each Linux machines in order to have the ability to take the images from remote machine by settings the insecure-registries and registry-mirrors as ...
0
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1answer
271 views

use mount with LUKS2

Back in times of LUKS1, it was possible to use a command like $ mount /dev/luks-encrypted-partition /mnt/a [enter passphrase upon being prompted] as a shortcut for $ cryptsetup luksOpen /dev/luks-...
0
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0answers
82 views

What are the best practices for device-mapper multipath?

Background: We are setting up the new storage for an HPC Compute cluster for applied statistics, bioinformatics, and genomics. Contrary to our expectations, an active-active configuration did not ...
1
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0answers
12 views

cache_writeback of thin-provisioning-tools running failed

I use Ubuntu 16.04 with kernel 5.4 and thin-provisioning-tools version 0.8.5 I want to test the cache_xml and cache_writeback tools of thin-provisioning, but it failed. It always failed and I don't ...
0
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0answers
318 views

sar -dp reports individual disks higher than their devicemapper logical volume

I am trying to figure out how sysstat is reporting the utilization of the device mapper logical volume, lower than the individual disks that make up the logical volume. I keep trying to do the math ...
-3
votes
1answer
180 views

VMWare device mapper size smaller than parition size

I am trying to understand what is going on with my VMWare instance. I have had 50GB partition that I extended to 150GB and resized the partition. However, the partition still shows that it only has ...
0
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2answers
279 views

How do you specify how much disk space for each mount point on vsphere?

I created a vm via the vsphere web client. The ESX version is 6.5 and the vsphere version is also 6.5 Via the menu: create virtual machine Option 2f: customize hardware Virtual Hardware: New Hard ...
1
vote
1answer
217 views

How to modify the "dm-*" value?

As I command multipath -ll, the output show like this. ocr3 (149455400000000000000000001000000ca0200000d000000) dm-9 IET,VIRTUAL-DISK [size=980M][features=0][hwhandler=0] \_ round-robin 0 [prio=0][...
1
vote
1answer
282 views

Cannot create PV on /dev/dm-NN (/dev/dm-N works)

I'm unable to create PVs on Multipath-Volumes that are available at /dev/dm-NN where N~[0-9] but I can create them on single digit devices like /dev/dm-9: # pvcreate /dev/dm-6 Physical volume "/dev/...
2
votes
2answers
904 views

Why is dmsetup failing when I try to create a snapshot?

I would like to create a COW device for an existing block device using dmsetup. The block device is: # blockdev --getsz /dev/loop0 3534848 I am trying to use a 256M ramdisk as the backing store: # ...
0
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1answer
129 views

Seeing Multiple Partition for same LUN

Anyone knows why I am seeing multiple device for the same LUN?I checked with storage team they only exposed 360000970000196801239533036304532 for this server but why I am seeing these many partition(...
4
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0answers
5k views

cryptsetup cannot close mapped device

When I run: LANG=C cryptsetup --debug luksClose /dev/mapper/Pool-A it fails as follows: device-mapper: remove ioctl on Pool-A failed: Device or resource busy Device /dev/mapper/Pool-A is still ...
11
votes
2answers
6k views

kvm to vmware migration - lvm based guest + multipathing

What is recommended way of migrate from kvm to vmware in case of lvm based guest with multipathing? I found that similar questions were already asked few years ago: How to migrate KVM based VMs ...
8
votes
1answer
17k views

how to correctly 'extend' a linux device mapper partition?

I am missing some concept with linux disk management, I have free space on a single physical volume that I want to to extend an ext4 file-system with, which is a logical volume. I look at fdisk -l - ...
0
votes
1answer
837 views

duplicate entries /dev/mapper

The system is Fedora 23. This occurred after a system upgrade. The issue is duplicate entries in /dev/mapper. As seen by /dev/mapper each partition is represented twice. How can the device based names ...
1
vote
1answer
824 views

I/O scheduling on LVM on dm-crypt

I have the following setup: Stock Debian stable (Linux kernel 3.16.7) running on Dell PowerEdge R320 Two SATA hard drives in RAID1 on a PERC H310 Mini controller, visible as /dev/sda dm-crypt target ...
1
vote
1answer
459 views

using same LVM volume for devicemapper and a bind mounted volume

I'm running an Amazon EC2 machine with a 512GB EBS mount. My plan is to split the EBS into two parts - one to be used by Docker 1.11 for its images (via devicemapper) and another to be bind-mounted to ...
1
vote
0answers
435 views

Is it possible to extend the data device of an Thin Provision pool setted by device mapper?

TL;DR : How can I extend the Thin-Pool if I'm not using LVM but Device Mapper itself directly? Detailed version: As far as I know, when we create a thin-pool by dmsetup, we can set a ...
3
votes
2answers
2k views

multipath, device mapper, and disk i/o scheduler

We have two machines with a multi path SAS controller, each with 12 physical disks attached. We were looking into some I/O speed oddness, and noticed that on one machine, where /dev/mpath/mpath*p1 ...
4
votes
0answers
240 views

How to disable write barrier on docker thinpooldev?

My server has very low disk performance if write barrier is enabled. As it has a disk controller with battery for the cache it is safe to add the "nobarrier" option to /etc/fstab. This makes a huge ...
1
vote
0answers
186 views

dmcache - is removing cache device without suspending safe?

I'm using plain dmcache for SSD cache - unmount procedure goes this way: umount fs suspend cache device remove cache device close lvm close LUKS shutdown However sometimes dmsetup doesn't allow me ...
10
votes
4answers
36k views

is /dev/dm-1 a partition or a whole block device?

Is there a way to figure out if /dev/dm-1 is a block device partition or a whole block device? If /dev/dm-1 is a partition, is there a way to find out the path to the corresponding whole block device?
0
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0answers
667 views

Linux, dev-mapper: How to mount a folder with different options than parent folder

I'm using CentOS 7.1 with device-mapper, and /home mounted as /dev/mapper/centos-home on /home type xfs (rw,relatime,seclabel,attr2,inode64,noquota) I'd like to include in fstab an entry for ...
20
votes
1answer
2k views

Why higher await time for DM multipath device than underlying device?

We have a CentOS 6.4 based server attached to Hitachi HNAS 3080 storage and observed the kernel remount the filesystem in read-only mode: May 16 07:31:03 GNS3-SRV-CMP-001 kernel: [1259725.675814] ...
14
votes
3answers
5k 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 /...
2
votes
1answer
2k views

How to rebuild a dmraid RAID10 array?

Q: How do I force a rebuild? The following describes the scenario. I've been experimenting with forcing a RAID10 to rebuild, so I could see what dmsetup status output should look like when a RAID is ...