Questions tagged [device-mapper]
The device-mapper tag has no usage guidance.
30
questions
0
votes
0
answers
187
views
How to get rid of “Duplicate IMA measurements will not be recorded in the IMA log.”?
In the journal of my Debian 12 kernel linux-image-6.1.0-10-amd64 version 6.1.37-1 I discovered the following lines:
…
… hostname systemd[1]: Starting systemd-journald.service - Journal Service …
… ...
- 101
0
votes
0
answers
18
views
Some "dispappered" dm-? files under the /dev directory
Recently I took over a few RHEL systems running with the native DM-multipath, which had been installed & configured by other persons.
My doubts focus on the following questions:
1). Why there ...
- 3
2
votes
0
answers
262
views
Data corruption after dmsetup suspend, reload, resume, and re-suspend
Consider the following series of events for a device-mapper crypt target, test, holding an ext4 filesystem. These three commands swap out the crypt target's table with a new (dummy) table. This ...
- 462
2
votes
0
answers
146
views
How to make a virtual disk image out of several parts?
During a process of moving to a virtualized infrastructure I encountered the following curious problem.
We want to evaluate everything first. This involves creating a virtual images of all required ...
- 11.2k
1
vote
0
answers
241
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 ...
- 1,105
0
votes
1
answer
786
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-...
- 161
0
votes
0
answers
212
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 ...
- 209
1
vote
0
answers
26
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 ...
- 161
0
votes
0
answers
742
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 ...
- 46
-3
votes
1
answer
473
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 ...
- 977
0
votes
2
answers
401
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 ...
- 105
1
vote
1
answer
563
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][...
- 21
1
vote
1
answer
451
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/...
- 860
2
votes
2
answers
2k
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:
# ...
- 43.8k
0
votes
1
answer
197
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(...
- 713
7
votes
1
answer
7k
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 ...
- 682
11
votes
3
answers
7k
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 ...
- 111
10
votes
1
answer
25k
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 - ...
- 1,944
0
votes
1
answer
1k
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 ...
- 141
1
vote
1
answer
1k
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 ...
- 193
1
vote
1
answer
540
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 ...
- 117
1
vote
0
answers
448
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 ...
- 11
3
votes
2
answers
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 ...
- 6,668
4
votes
0
answers
278
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 ...
- 909
1
vote
0
answers
274
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 ...
- 363
12
votes
4
answers
44k
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?
- 891
0
votes
0
answers
958
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 ...
- 143
20
votes
1
answer
3k
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] ...
- 778
14
votes
3
answers
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 /...
- 244k
2
votes
1
answer
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 ...
- 21