As per the thin provisioning docs for creating the pool:
$data_block_size gives the smallest unit of disk space that can be
allocated at a time expressed in units of 512-byte sectors.
$data_block_size must be between 128 (64KB) and 2097152 (1GB) and a
multiple of 128 (64KB). $data_block_size cannot be changed after the
thin-pool is created. People primarily interested in thin provisioning
may want to use a value such as 1024 (512KB). People doing lots of
snapshotting may want a smaller value such as 128 (64KB).
The switch from 512 (which we used before) to 128 (recommended above
for lots of snapshoting) means a simple container creation (based on the
mattdm/fedora:f19 image) adds 1 MB of diskspace rather than 3.6.
This seems more in tune with how docker is typically used.
Upstream-commit: 8abcc8e713fdf6229d65dec23e6e104f8040d704
Component: engine
This way the devicemapper prefix stays stable even if we're not
using loopback mounted devices.
Upstream-commit: e6a73e65a23163273fa63d54b8f12530f7eef104
Component: engine
This separates out the DeviceSet logic a bit better from the raw
device mapper operations.
devicemapper: Serialize addess to the devicemapper deviceset
This code is not safe to run in multiple threads at the same time,
and neither is libdevmapper.
DeviceMapper: Move deactivate into UnmountDevice
This way the deactivate is atomic wrt othe device mapper operations
and will not fail with EBUSY if someone else starts a devicemapper
operation inbetween unmount and deactivate.
devmapper: Fix loopback mounting regression
Some changes were added to attach_loop_device which added
a perror() in a place that caused it to override errno so that
a later errno != EBUSY failed. This fixes that and cleans up
the error reporting a bit.
devmapper: Build on old kernels without LOOP_CTL_GET_FREE define
Upstream-commit: c77697a45ca615f66351a7363e93c3903e92553f
Component: engine
Typo in the loop-control code made it always fall back to the
old method of opening loopback devices.
Upstream-commit: cc28829429f5f11da287ecb75ee5b3e5f05d31ad
Component: engine
The init layer needs to be topmost to make sure certain files
are always there (for instance, the ubuntu:12.10 image wrongly
has /dev/shm being a symlink to /run/shm, and we need to override
that). However, previously the devmapper code implemented the
init layer by putting it in the base devmapper device, which meant
layers above it could override these files (so that ubuntu:12.10
broke).
So, instead we put the base layer in *each* images devmapper device.
This is "safe" because we still have the pristine layer data
in the layer directory. Also, it means we diff the container
against the image with the init layer applied, so it won't show
up in diffs/commits.
Upstream-commit: c199ed228baf0e5d33b7739cc2442a32dece7020
Component: engine
We unmount all mounts and deactivate all device mapper devices to
make sure we're left with no leftovers after the test.
Upstream-commit: c6e8813c979bbea8832f47dc6468e805a1a18c3e
Component: engine
Right now this does nothing but add a new layer, but it means
that all DeviceMounts are paired with DeviceUnmounts so that we
can track (and cleanup) active mounts.
Upstream-commit: 251a7ed437c17ecb66d33782f0b42633033198dd
Component: engine
This removes some Debugf() calls and chages some direct prints to
Debugf(). This means we don't get a bunch of spew when running the
tests.
Upstream-commit: bc7fa7b95773d638754eb72e7921ac328acb2ad6
Component: engine
This means the default is "docker-*", but for tests we get separate
prefixes for each test.
Upstream-commit: 8f343ea65a05b374ffa64940a1946abf28402689
Component: engine
This is a module that uses the device-mapper create CoW snapshots
You instantiate a DeviceSetDM object on a specified root (/var/lib/docker),
and it will create a subdirectory there called "loopback". It will
contain two sparse files which are loopback mounted into
a thin-pool device-mapper device called "docker-pool".
We then create a base snapshot in the pool with an empty filesystem
which can be used as a base for docker snapshots. It also keeps track
of the mapping between docker image ids and the snapshots in the pool.
Typical use of is something like (without error checking):
devices = NewDeviceSetDM("/var/lib/docker")
devices.AddDevice(imageId, "") // "" is the base image id
devices.MountDevice(imageId, "/mnt/image")
... extract base image to /mnt/image
devices.AddDevice(containerId, imageId)
devices.MountDevice(containerId, "/mnt/container")
... start container at /mnt/container
Upstream-commit: 0b12702c0c9753cbb18a942bac2600b036e4f80e
Component: engine
