From 3716e20af5b583c3e15661aab657168176baa01e Mon Sep 17 00:00:00 2001 From: mulhern Date: Mon, 27 Nov 2017 10:02:41 -0500 Subject: dm cache: delete obsoleted paragraph in cache.txt The 'mq' policy is no longer the default policy, and the default policy, 'smq', does not store hit counts. Signed-off-by: mulhern Signed-off-by: Mike Snitzer --- Documentation/device-mapper/cache.txt | 5 ----- 1 file changed, 5 deletions(-) (limited to 'Documentation/device-mapper/cache.txt') diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt index cdfd0feb294e..043524409221 100644 --- a/Documentation/device-mapper/cache.txt +++ b/Documentation/device-mapper/cache.txt @@ -143,11 +143,6 @@ the policy how big this chunk is, but it should be kept small. Like the dirty flags this data is lost if there's a crash so a safe fallback value should always be possible. -For instance, the 'mq' policy, which is currently the default policy, -uses this facility to store the hit count of the cache blocks. If -there's a crash this information will be lost, which means the cache -may be less efficient until those hit counts are regenerated. - Policy hints affect performance, not correctness. Policy messaging -- cgit v1.2.3 From 1346638e5f80588dfafbf07315f72b84c2ab1113 Mon Sep 17 00:00:00 2001 From: mulhern Date: Mon, 27 Nov 2017 10:02:42 -0500 Subject: dm cache: be consistent in specifying sectors and SI units in cache.txt Signed-off-by: mulhern Signed-off-by: Mike Snitzer --- Documentation/device-mapper/cache.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation/device-mapper/cache.txt') diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt index 043524409221..79c7b6dc88ae 100644 --- a/Documentation/device-mapper/cache.txt +++ b/Documentation/device-mapper/cache.txt @@ -59,7 +59,7 @@ Fixed block size The origin is divided up into blocks of a fixed size. This block size is configurable when you first create the cache. Typically we've been using block sizes of 256KB - 1024KB. The block size must be between 64 -(32KB) and 2097152 (1GB) and a multiple of 64 (32KB). +sectors (32KB) and 2097152 sectors (1GB) and a multiple of 64 sectors (32KB). Having a fixed block size simplifies the target a lot. But it is something of a compromise. For instance, a small part of a block may be @@ -119,7 +119,7 @@ doing here to avoid migrating during those peak io moments. For the time being, a message "migration_threshold <#sectors>" can be used to set the maximum number of sectors being migrated, -the default being 204800 sectors (or 100MB). +the default being 204800 sectors (100MB). Updating on-disk metadata ------------------------- -- cgit v1.2.3 From 9614e2ba9161c7f5419f4212fa6057d2a65f6ae6 Mon Sep 17 00:00:00 2001 From: John Pittman Date: Tue, 30 Jan 2018 16:39:00 -0500 Subject: dm cache: Documentation: update default migration_throttling value In commit f8350daf7af0 ("dm cache: tune migration throttling") the value for DEFAULT_MIGRATION_THRESHOLD was decreased from 204800 to 2048. Edit device-mapper/cache.txt to reflect the correct default value for migration_threshold. Signed-off-by: John Pittman Signed-off-by: Mike Snitzer --- Documentation/device-mapper/cache.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation/device-mapper/cache.txt') diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt index 79c7b6dc88ae..ff0841711fd5 100644 --- a/Documentation/device-mapper/cache.txt +++ b/Documentation/device-mapper/cache.txt @@ -119,7 +119,7 @@ doing here to avoid migrating during those peak io moments. For the time being, a message "migration_threshold <#sectors>" can be used to set the maximum number of sectors being migrated, -the default being 204800 sectors (100MB). +the default being 2048 sectors (1MB). Updating on-disk metadata ------------------------- -- cgit v1.2.3