Lines Matching full:vdo
3 dm-vdo
6 The dm-vdo (virtual data optimizer) device mapper target provides
9 with any file system. The vdo target does not protect against data
11 it. It is strongly recommended that lvm be used to manage vdo volumes. See
17 Formatting a vdo volume requires the use of the 'vdoformat' tool, available
20 https://github.com/dm-vdo/vdo/
22 In most cases, a vdo target will recover from a crash automatically the
26 data-loss, a positive action must be taken to bring vdo out of read-only
28 prepare a read-only vdo to exit read-only mode. After running this tool,
29 the vdo target will rebuild its metadata the next time it is
30 started. Although some data may be lost, the rebuilt vdo's metadata will be
34 inspect a vdo target's on-disk metadata. Fortunately, these tools are
35 rarely needed except by dm-vdo developers.
40 Each vdo volume reserves 3GB of space for metadata, or more depending on
44 be computed with the vdo estimator tool, which is available at:
46 https://github.com/dm-vdo/vdoestimator/
56 <offset> <logical device size> vdo V4 <storage device>
64 The offset, in sectors, at which the vdo volume's logical
68 The size of the device which the vdo volume will service,
69 in sectors. Must match the current logical size of the vdo
73 The device holding the vdo volume's data and metadata.
76 The size of the device holding the vdo volume, as a number
77 of 4096-byte blocks. Must match the current size of the vdo
81 The minimum I/O size for this vdo volume to accept, in
115 outside the vdo volume, threads of this type allow the vdo
121 storage. Threads of this type allow the vdo volume to
147 the vdo is chosen; the vdo storage device must be large
155 blocks. I/O requests to a vdo volume are normally split
157 However, discard requests to a vdo volume can be
176 A modified table may be loaded into a running, non-suspended vdo volume.
182 successful resume vdo will store the new values and require them on future
186 underlying storage device. Additionally, when formatting the vdo device, a
193 Start a previously-formatted vdo volume with 1 GB logical space and 1 GB
199 "0 2097152 vdo V4 /dev/dm-1 262144 4096 32768 16380"
206 "0 8388608 vdo V4 /dev/dm-1 262144 4096 32768 16380"
214 "0 8388608 vdo V4 /dev/dm-1 524288 4096 32768 16380"
222 "0 10485760 vdo V4 /dev/dm-1 786432 4096 32768 16380 maxDiscard 8"
225 Stop the vdo volume.
231 Start the vdo volume again. Note that the logical and physical device sizes
237 "0 10485760 vdo V4 /dev/dm-1 786432 512 65550 5000 hash 1 logical 3 physical 2"
241 All vdo devices accept messages in the form:
250 Outputs the current view of the vdo statistics. Mostly used
255 Outputs useful vdo configuration information. Mostly used
256 by users who want to recreate a similar VDO volume and
262 a hung vdo. Optional parameters to specify structures to
267 vdo: Most of the structures managing on-disk data
268 queues: Basic information about each vdo thread
270 default: Equivalent to 'queues vdo'
274 Perform a default dump next time vdo shuts down.
286 The name of the vdo volume.
289 The current operating mode of the vdo volume; values may be
292 'read-only' (an error has occurred that forces the vdo
296 Whether the vdo volume is currently in recovery mode;
301 The current state of the deduplication index in the vdo
306 The current state of compression in the vdo volume; values
310 The number of physical blocks in use by the vdo volume.
313 The total number of physical blocks the vdo volume may use;
315 <used physical blocks> is the number of blocks the vdo
321 A vdo target requires a fixed 38 MB of RAM along with the following amounts
338 The vdo driver has a numeric parameter 'log_level' which controls the
345 When using dm-vdo, it is important to be aware of the ways in which its
350 an existing block generally requires a vdo to have a free block
354 blocks lets the vdo release references for those blocks. If the vdo is
360 - Assuming the underlying storage properly implements flush requests, vdo
364 - Each write to a vdo target entails a significant amount of processing.
365 However, much of the work is paralellizable. Therefore, vdo targets
372 The vdo device has many options, and it can be difficult to make optimal
374 configuration options must be set when a vdo target is started, and cannot
377 workloads should be performed before deploying vdo in production
381 service a request for any logical address, a vdo must load the portion of
384 default, a vdo allocates 128 MB of metadata cache in RAM to support
402 bio's callback can not be controlled by the vdo itself. Usually one thread