conf/example.conf.in | 59 ++++++++++++++++++++++++++++------------------------

 1 file changed, 32 insertions(+), 27 deletions(-)

diff --git a/conf/example.conf.in b/conf/example.conf.in

index 0c2d378..a54dc62 100644

--- a/conf/example.conf.in

+++ b/conf/example.conf.in

@@ -490,10 +490,19 @@ allocation {

 	# This configuration option has an automatic default value.

 	# vdo_use_deduplication = 1

-	# Configuration option allocation/vdo_emulate_512_sectors.

-	# Specifies that the VDO volume is to emulate a 512 byte block device.

+	# Configuration option allocation/vdo_use_metadata_hints.

+	# Enables or disables whether VDO volume should tag its latency-critical

+	# writes with the REQ_SYNC flag. Some device mapper targets such as dm-raid5

+	# process writes with this flag at a higher priority.

+	# Default is enabled.

 	# This configuration option has an automatic default value.

-	# vdo_emulate_512_sectors = 0

+	# vdo_use_metadata_hints = 1

+

+	# Configuration option allocation/vdo_minimum_io_size.

+	# The minimum IO size for VDO volume to accept, in bytes.

+	# Valid values are 512 or 4096. The recommended and default value is 4096.

+	# This configuration option has an automatic default value.

+	# vdo_minimum_io_size = 4096

 	# Configuration option allocation/vdo_block_map_cache_size_mb.

 	# Specifies the amount of memory in MiB allocated for caching block map

@@ -504,10 +513,10 @@ allocation {

 	# vdo_block_map_cache_size_mb = 128

 	# Configuration option allocation/vdo_block_map_period.

-	# Tunes the quantity of block map updates that can accumulate

-	# before cache pages are flushed to disk. The value must be

-	# at least 1 and less then 16380.

-	# A lower value means shorter recovery time but lower performance.

+	# The speed with which the block map cache writes out modified block map pages.

+	# A smaller era length is likely to reduce the amount time spent rebuilding,

+	# at the cost of increased block map writes during normal operation.

+	# The maximum and recommended value is 16380; the minimum value is 1.

 	# This configuration option has an automatic default value.

 	# vdo_block_map_period = 16380

@@ -527,22 +536,6 @@ allocation {

 	# This configuration option has an automatic default value.

 	# vdo_index_memory_size_mb = 256

-	# Configuration option allocation/vdo_use_read_cache.

-	# Enables or disables the read cache within the VDO volume.

-	# The cache should be enabled if write workloads are expected

-	# to have high levels of deduplication, or for read intensive

-	# workloads of highly compressible data.

-	# This configuration option has an automatic default value.

-	# vdo_use_read_cache = 0

-

-	# Configuration option allocation/vdo_read_cache_size_mb.

-	# Specifies the extra VDO volume read cache size in MiB.

-	# This space is in addition to a system-defined minimum.

-	# The value must be less then 16TiB and 1.12 MiB of memory

-	# will be used per MiB of read cache specified, per bio thread.

-	# This configuration option has an automatic default value.

-	# vdo_read_cache_size_mb = 0

-

 	# Configuration option allocation/vdo_slab_size_mb.

 	# Specifies the size in MiB of the increment by which a VDO is grown.

 	# Using a smaller size constrains the total maximum physical size

@@ -551,7 +544,7 @@ allocation {

 	# vdo_slab_size_mb = 2048

 	# Configuration option allocation/vdo_ack_threads.

-	# Specifies the number of threads to use for acknowledging

+	# Specifies the number of threads   to use for acknowledging

 	# completion of requested VDO I/O operations.

 	# The value must be at in range [0..100].

 	# This configuration option has an automatic default value.

@@ -618,6 +611,18 @@ allocation {

 	#         Data which has not been flushed is not guaranteed to persist in this mode.

 	# This configuration option has an automatic default value.

 	# vdo_write_policy = "auto"

+

+	# Configuration option allocation/vdo_max_discard.

+	# Specified te maximum size of discard bio accepted, in 4096 byte blocks.

+	# I/O requests to a VDO volume are normally split into 4096-byte blocks,

+	# and processed up to 2048 at a time. However, discard requests to a VDO volume

+	# can be automatically split to a larger size, up to <max discard> 4096-byte blocks

+	# in a single bio, and are limited to 1500 at a time.

+	# Increasing this value may provide better overall performance, at the cost of

+	# increased latency for the individual discard requests.

+	# The default and minimum is 1. The maximum is UINT_MAX / 4096.

+	# This configuration option has an automatic default value.

+	# vdo_max_discard = 1

 }

 # Configuration section log.

@@ -898,14 +903,14 @@ global {

 	mirror_segtype_default = "@DEFAULT_MIRROR_SEGTYPE@"

 	# Configuration option global/support_mirrored_mirror_log.

+	# Configuration option global/support_mirrored_mirror_log.

 	# Enable mirrored 'mirror' log type for testing.

-	#

+	# 

 	# This type is deprecated to create or convert to but can

 	# be enabled to test that activation of existing mirrored

 	# logs and conversion to disk/core works.

-	#

+	# 

 	# Not supported for regular operation!

-	#

 	support_mirrored_mirror_log = 0

 	# Configuration option global/raid10_segtype_default.