Block layer component of the Linux kernel to create and manage virtual block devices atop of physical block devices. QUESTIONS MUST BE PROGRAMMING RELATED.
Questions tagged [device-mapper]
72 questions
0
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1 answer
What is [loop0] process for?
I'm running apache in a docker container on a CentOS 7 machine with devicemapper (on a dedicated volume group not on loopback file).
After a few requests, system load dramatically increase even up to 20. Since the cpu load is reasonably low, i…
user1328830
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1 answer
Set disc quota with DeviceMapper
I have changed storage plugin to DeviceMapper. Docker info gives following output.
Server Version: 1.9.0
Storage Driver: devicemapper
Pool Name: docker-253:1-16-pool
Pool Blocksize: 65.54 kB
Base Device Size: 107.4 GB
Backing Filesystem: extfs
…
user4725754
0
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1 answer
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 difference in performance. I want to the same for…
Peter
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0 answers
Docker: device mapper file system gets corrupted
I'm using docker with device mapper on Redhat 2.6.32.
Docker version is 1.5.0.
When docker uses all the data space allocated to docker (Data Space Used value reaches Data Space Total, which is 107G by default) the device mapper file system gets…
Emil Salageanu
- 997
- 1
- 10
- 24
0
votes
1 answer
Error when building a Docker container
The command docker build fails with error :
Error getting container f43128eda488c88a3b2e111aafb30b80a44faaead33bcf02f8bffd7ae1832753 from driver devicemapper: Error mounting…
Porfus
- 129
- 1
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- 7
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0 answers
Docker - managing size of containers
I need more than 10G of disc space in my container to run application. But 10G is set as a default maximum size of containers. I am running RHEL 7, so devicemapper as well. I've found this:
docker -d --storage-opt dm.basesize=25G
Before that, what…
Irt
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1 answer
Is Docker slow when using device mapper on Fedora?
I am experimenting docker and I plan to dockerize my project's CI infratsructure.
I am building dockerfiles on 3 different machines: Fedora, Ubuntu, and Boot2Docker (a virtiual machine under windows).
Docker builds on fedora are a lot slower…
Emil Salageanu
- 997
- 1
- 10
- 24
0
votes
1 answer
Read a actual physical block
I have LBN->PBN map.
LBN - Logical Block Number.
PBN - Physical Block Number.
I can get each (LBN, PBN) entry from the above map.
Is there any API that I can use to read the data from the actual block device using this PBN. I am currently working in…
7jan
- 11
0
votes
1 answer
dm-zero device mount errors
I am trying to create a dm-zero device and mount it,but getting the following errors during mount.I have been stuck here for very long. Any help will be appreciated.
Error
mount: wrong fs type, bad option, bad superblock on /dev/mapper/zero_1,
…
user3864733
- 13
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- 3
0
votes
1 answer
Docker: Layering on top of shared volume
I want to use a shared volume in a container but the updates to data in the shared volume cannot go to the underlying directory on the host and these updates should be discarded when the container goes away.
For example:
Create shared directory…
RobertG
- 1
- 2
-1
votes
1 answer
After uninstalling Docker from RHEL, having issues with removing associated files
I installed Docker EE on RHEL. Now when I need to uninstall, as per the instructions on the Docs, i need to run sudo rm -rf /var/lib/docker.
This however gives me the following errors:
rm: cannot remove…
aman_novice
- 1,027
- 3
- 13
- 31
-1
votes
1 answer
Softlayer: determine scsi disk Softlayer-ID using the dev mapper device id
In a setup of a multiple iscsi disks attached to a Linux host (LVM pools setup), I want to be able to take a snapshot of a specific disk, using Softlayer API.
How can I know the id or the LUN name of the iscsi device from the Linux device name. …
csny
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