device-mapper | 易学教程

According to the union file system, does image actually container another image?

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问题 In Docker, an image is a stack of Read-only image layers. We also know that images share layers or other images. My question is about how this sharing mechanism work. Does an image have pointers to the Docker storage driver or do they actually contain other layers? If the first one is true, does that mean Dockerfile saves those layers into daemon and the image is the instruction of retrieving those layers orderly? 回答1: It depends on your storage driver: Docker uses storage drivers to manage

According to the union file system, does image actually container another image?

阅读更多关于 According to the union file system, does image actually container another image?

According to the union file system, does image actually container another image?

阅读更多关于 According to the union file system, does image actually container another image?

create device mapper target

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问题 I am trying to implement device mapper target by referring to the already existing ones dm-linear, dm-snapshot, dm-cache etc. In my implementation, I need to perform a read/modify/write operation on a certain sector range. Since the device mapper directly talks to the block layer, I am not sure what data structures/functions to use to read the sectors in the memory, modify the buffer and write it back to another sector range. At the application level, we have syscalls and below we have vfs

Can't run Docker container due device mapper error

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问题 I just can't create and run new containers in Docker anymore. But in the same time a can run previously created containers. When I try to do something like this: [user@host ~ ] docker run --name=fpm-5.3 debian:jessie 2014/07/12 07:34:08 Error: Error running DeviceCreate (createSnapDevice) dm_task_run failed From docker.log : 2014/07/12 05:57:11 POST /v1.12/containers/create?name=fpm-5.3 [f56fcb6f] +job create(fpm-5.3) Error running DeviceCreate (createSnapDevice) dm_task_run failed [f56fcb6f]

Implications of exposing /var/lib/docker over NFS to serve hosts with limited memory

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问题 What are the implications of exporting /var/lib/docker over NFS? The idea is to store the docker images in a server and export it to hosts which has limited memory to store and run containers. This would be useful to avoid having each host download and store it's own library of docker image. The hosts may make use of FS-Cache to limit the data transfer over network. 回答1: The /var/lib/docker directory is designed to be exclusively accessed by a single daemon, and should never be shared with

How to clean docker devicemapper folder properly ?

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问题 I have some problem about the storage. The folder /var/lib/docker/devicemapper/ is taking 50% of my storage. In the folder /var/lib/docker/devicemapper/mnt , I have many empty folders. How can I properly clean docker devicemapper and remove all unused mapping ? 回答1: With recent versions of Docker you can see the space used with: docker system df and prune it with: docker system prune The above command combines the prune command that exists for volumes, containers, images and networks: docker

How to clean docker devicemapper folder properly ?

阅读更多关于 How to clean docker devicemapper folder properly ?

I have some problem about the storage. The folder /var/lib/docker/devicemapper/ is taking 50% of my storage. In the folder /var/lib/docker/devicemapper/mnt , I have many empty folders. How can I properly clean docker devicemapper and remove all unused mapping ? With recent versions of Docker you can see the space used with: docker system df and prune it with: docker system prune The above command combines the prune command that exists for volumes, containers, images and networks: docker volume prune docker container prune docker image prune docker network prune Each command has a --help option

create device mapper target

阅读更多关于 create device mapper target

I am trying to implement device mapper target by referring to the already existing ones dm-linear, dm-snapshot, dm-cache etc. In my implementation, I need to perform a read/modify/write operation on a certain sector range. Since the device mapper directly talks to the block layer, I am not sure what data structures/functions to use to read the sectors in the memory, modify the buffer and write it back to another sector range. At the application level, we have syscalls and below we have vfs_read/vfs_write. Is there anything similar for device mapper layer? I have been stuck here for very long.

Can't run Docker container due device mapper error

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I just can't create and run new containers in Docker anymore. But in the same time a can run previously created containers. When I try to do something like this: [user@host ~ ] docker run --name=fpm-5.3 debian:jessie 2014/07/12 07:34:08 Error: Error running DeviceCreate (createSnapDevice) dm_task_run failed From docker.log : 2014/07/12 05:57:11 POST /v1.12/containers/create?name=fpm-5.3 [f56fcb6f] +job create(fpm-5.3) Error running DeviceCreate (createSnapDevice) dm_task_run failed [f56fcb6f] -job create(fpm-5.3) = ERR (1) [error] server.go:1025 Error: Error running DeviceCreate