diff options
Diffstat (limited to 'Documentation/admin-guide/device-mapper')
5 files changed, 93 insertions, 12 deletions
diff --git a/Documentation/admin-guide/device-mapper/delay.rst b/Documentation/admin-guide/device-mapper/delay.rst index 917ba8c33359..4d667228e744 100644 --- a/Documentation/admin-guide/device-mapper/delay.rst +++ b/Documentation/admin-guide/device-mapper/delay.rst @@ -3,29 +3,52 @@ dm-delay ======== Device-Mapper's "delay" target delays reads and/or writes -and maps them to different devices. +and/or flushs and optionally maps them to different devices. -Parameters:: +Arguments:: <device> <offset> <delay> [<write_device> <write_offset> <write_delay> [<flush_device> <flush_offset> <flush_delay>]] -With separate write parameters, the first set is only used for reads. +Table line has to either have 3, 6 or 9 arguments: + +3: apply offset and delay to read, write and flush operations on device + +6: apply offset and delay to device, also apply write_offset and write_delay + to write and flush operations on optionally different write_device with + optionally different sector offset + +9: same as 6 arguments plus define flush_offset and flush_delay explicitely + on/with optionally different flush_device/flush_offset. + Offsets are specified in sectors. + Delays are specified in milliseconds. + Example scripts =============== :: - #!/bin/sh - # Create device delaying rw operation for 500ms - echo "0 `blockdev --getsz $1` delay $1 0 500" | dmsetup create delayed + # + # Create mapped device named "delayed" delaying read, write and flush operations for 500ms. + # + dmsetup create delayed --table "0 `blockdev --getsz $1` delay $1 0 500" :: + #!/bin/sh + # + # Create mapped device delaying write and flush operations for 400ms and + # splitting reads to device $1 but writes and flushs to different device $2 + # to different offsets of 2048 and 4096 sectors respectively. + # + dmsetup create delayed --table "0 `blockdev --getsz $1` delay $1 2048 0 $2 4096 400" +:: #!/bin/sh - # Create device delaying only write operation for 500ms and - # splitting reads and writes to different devices $1 $2 - echo "0 `blockdev --getsz $1` delay $1 0 0 $2 0 500" | dmsetup create delayed + # + # Create mapped device delaying reads for 50ms, writes for 100ms and flushs for 333ms + # onto the same backing device at offset 0 sectors. + # + dmsetup create delayed --table "0 `blockdev --getsz $1` delay $1 0 50 $2 0 100 $1 0 333" diff --git a/Documentation/admin-guide/device-mapper/dm-crypt.rst b/Documentation/admin-guide/device-mapper/dm-crypt.rst index aa2d04d95df6..4467f6d4b632 100644 --- a/Documentation/admin-guide/device-mapper/dm-crypt.rst +++ b/Documentation/admin-guide/device-mapper/dm-crypt.rst @@ -113,6 +113,11 @@ same_cpu_crypt The default is to use an unbound workqueue so that encryption work is automatically balanced between available CPUs. +high_priority + Set dm-crypt workqueues and the writer thread to high priority. This + improves throughput and latency of dm-crypt while degrading general + responsiveness of the system. + submit_from_crypt_cpus Disable offloading writes to a separate thread after encryption. There are some situations where offloading write bios from the @@ -141,6 +146,11 @@ integrity:<bytes>:<type> integrity for the encrypted device. The additional space is then used for storing authentication tag (and persistent IV if needed). +integrity_key_size:<bytes> + Optionally set the integrity key size if it differs from the digest size. + It allows the use of wrapped key algorithms where the key size is + independent of the cryptographic key size. + sector_size:<bytes> Use <bytes> as the encryption unit instead of 512 bytes sectors. This option can be in range 512 - 4096 bytes and must be power of two. @@ -155,6 +165,27 @@ iv_large_sectors The <iv_offset> must be multiple of <sector_size> (in 512 bytes units) if this flag is specified. +integrity_key_size:<bytes> + Use an integrity key of <bytes> size instead of using an integrity key size + of the digest size of the used HMAC algorithm. + + +Module parameters:: + max_read_size + Maximum size of read requests. When a request larger than this size + is received, dm-crypt will split the request. The splitting improves + concurrency (the split requests could be encrypted in parallel by multiple + cores), but it also causes overhead. The user should tune this parameters to + fit the actual workload. + + max_write_size + Maximum size of write requests. When a request larger than this size + is received, dm-crypt will split the request. The splitting improves + concurrency (the split requests could be encrypted in parallel by multiple + cores), but it also causes overhead. The user should tune this parameters to + fit the actual workload. + + Example scripts =============== LUKS (Linux Unified Key Setup) is now the preferred way to set up disk diff --git a/Documentation/admin-guide/device-mapper/dm-integrity.rst b/Documentation/admin-guide/device-mapper/dm-integrity.rst index d8a5f14d0e3c..c2e18ecc065c 100644 --- a/Documentation/admin-guide/device-mapper/dm-integrity.rst +++ b/Documentation/admin-guide/device-mapper/dm-integrity.rst @@ -92,6 +92,11 @@ Target arguments: allowed. This mode is useful for data recovery if the device cannot be activated in any of the other standard modes. + I - inline mode - in this mode, dm-integrity will store integrity + data directly in the underlying device sectors. + The underlying device must have an integrity profile that + allows storing user integrity data and provides enough + space for the selected integrity tag. 5. the number of additional arguments diff --git a/Documentation/admin-guide/device-mapper/vdo.rst b/Documentation/admin-guide/device-mapper/vdo.rst index 7e1ecafdf91e..a14e6d3e787c 100644 --- a/Documentation/admin-guide/device-mapper/vdo.rst +++ b/Documentation/admin-guide/device-mapper/vdo.rst @@ -241,6 +241,7 @@ Messages All vdo devices accept messages in the form: :: + dmsetup message <target-name> 0 <message-name> <message-parameters> The messages are: @@ -250,7 +251,12 @@ The messages are: by the vdostats userspace program to interpret the output buffer. - dump: + config: + Outputs useful vdo configuration information. Mostly used + by users who want to recreate a similar VDO volume and + want to know the creation configuration used. + + dump: Dumps many internal structures to the system log. This is not always safe to run, so it should only be used to debug a hung vdo. Optional parameters to specify structures to diff --git a/Documentation/admin-guide/device-mapper/verity.rst b/Documentation/admin-guide/device-mapper/verity.rst index a65c1602cb23..8c3f1f967a3c 100644 --- a/Documentation/admin-guide/device-mapper/verity.rst +++ b/Documentation/admin-guide/device-mapper/verity.rst @@ -87,6 +87,15 @@ panic_on_corruption Panic the device when a corrupted block is discovered. This option is not compatible with ignore_corruption and restart_on_corruption. +restart_on_error + Restart the system when an I/O error is detected. + This option can be combined with the restart_on_corruption option. + +panic_on_error + Panic the device when an I/O error is detected. This option is + not compatible with the restart_on_error option but can be combined + with the panic_on_corruption option. + ignore_zero_blocks Do not verify blocks that are expected to contain zeroes and always return zeroes instead. This may be useful if the partition contains unused blocks @@ -142,8 +151,15 @@ root_hash_sig_key_desc <key_description> already in the secondary trusted keyring. try_verify_in_tasklet - If verity hashes are in cache, verify data blocks in kernel tasklet instead - of workqueue. This option can reduce IO latency. + If verity hashes are in cache and the IO size does not exceed the limit, + verify data blocks in bottom half instead of workqueue. This option can + reduce IO latency. The size limits can be configured via + /sys/module/dm_verity/parameters/use_bh_bytes. The four parameters + correspond to limits for IOPRIO_CLASS_NONE, IOPRIO_CLASS_RT, + IOPRIO_CLASS_BE and IOPRIO_CLASS_IDLE in turn. + For example: + <none>,<rt>,<be>,<idle> + 4096,4096,4096,4096 Theory of operation =================== |