Commit 09ee269d ("devmapper: Add option for specifying the thin pool
blocksize") also switched the default dm-thin-pool blocksize from 64K to
512K. That change unfortunately breaks the activation of dm-thin-pool
devices that were previously created using a 64K blocksize. Here is an
example of the dm-thin-pool activation failure users may experience:
device-mapper: thin: 253:4: pool target (204800 blocks) too small: expected 1638400
device-mapper: table: 253:4: thin-pool: preresume failed, error = -22
The reason for this is docker is passing 512K as the blocksize for a
dm-thin-pool that was previously created using a 64K blocksize. Docker
doesn't record the blocksize the is used when it creates a dm-thin-pool.
Until now it never had a need to do so because the blocksize was always
hardcoded. The dm-thin-pool blocksize must be the same every time a
dm-thin-pool is activated.
As a stop-gap fix, revert to using 64K for the default blocksize.
But we do need a proper fix for this now that 'dm.blocksize' is exposed
as a proper storage option. One possible fix would be to record the
blocksize for each dm-thin-pool that docker creates and to pass that
recorded blocksize down in the dmsetup table load each time the
dm-thin-pool is activated (this would be comparable to what lvm2 does).
Docker-DCO-1.1-Signed-off-by: Mike Snitzer <snitzer@redhat.com> (github: snitm)
Add dm.blocksize option that you can use with --storage-opt to set a
specific blocksize for the thin provisioning pool.
Also change the default dm-thin-pool blocksize from 64K to 512K. This
strikes a balance between the desire to have smaller blocksize given
docker's use of snapshots versus the desire to have more performance
that comes with using a larger blocksize. But if very small files will
be used on average the user is encouraged to override this default.
Docker-DCO-1.1-Signed-off-by: Mike Snitzer <snitzer@redhat.com> (github: snitm)
Device Mapper needs device sizes in binary (1024) multiples. Otherwise
kernel checks can find that the specified thin-pool device sizes aren't
a multiple of the specified thin-pool blocksize.
The name for "RAMInBytes" is likely too narrow given the new consumers
but... Also add "tebibyte" support to RAMInBytes.
Docker-DCO-1.1-Signed-off-by: Mike Snitzer <snitzer@redhat.com> (github: snitm)
The blkdiscard hack we do on container/image delete is pretty slow, but
required to restore space to the "host" root filesystem. However, it
is pretty useless on raw devices, and you may not need it in development
either.
In a simple test of the devicemapper backend on loopback the time to
delete 20 container went from 11 seconds to 0.4 seconds with
--storage-opt blkdiscard=false.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
This adds dm.datadev and dm.metadatadev options that you can use with
--storage-opt to set to specific devices to use for the thin
provisioning pool.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
This adds the following --storage-opts for the daemon:
dm.fs: The filesystem to use for the base image
dm.mkfsarg: Add an argument to the mkfs command for the base image
dm.mountopt: Add a mount option for devicemapper mount
Currently supported filesystems are xfs and ext4.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
This allows setting these settings to be passed:
dm.basesize
dm.loopdatasize
dm.loopmetadatasize
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
If we can't even get the current device mapper driver version, then
we cleanly fail the devmapper driver as not supported and fall back
on the next one.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
There is no reason to do discard durink mkfs, as the filesystem
is on a newly allocated device anyway. Discard is a slow operation,
so this may help initial startup a bit, especially if you use a larger
thin pool.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
This has every container using the docker daemon's pid for the processes
label so it does not work correctly.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
This allows multiple instances of the backend in different containers
to access devices (although generally only one can modify/create them).
Any old metadata is converted on the first run.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Instead of globally keeping track of the free device ids we just
start from 0 each run and handle EEXIST error and try the next one.
This way we don't need any global state for the device ids, which
means we can read device metadata lazily. This is important for
multi-process use of the backend.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
This moves the EBUSY detection to devmapper.go, and then returns
a real ErrBusy that deviceset uses.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
We used to mount in Create() to be able to create a few files that
needs to be in each device. However, this mount is problematic for
selinux, as we need to set the mount label at mount-time, and it
is not known at the time of Create().
This change just moves the file creation to first Get() call and
drops the mount from Create(). Additionally, this lets us remove
some complexities we had to avoid an extra unmount+mount cycle.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
