[PATCH] multipathd: update defaults

[PATCH] multipathd: update defaults

[Hannes Reinecke]

For years I've been telling our customers to use the 'tur' checker
as the current default 'directio' will cause spurious path failures
under high load.

And for several versions (years, even) the linux kernel has the ability
to correctly detect the device handler, so we should be making
'retain_hw_handler' the default.
And if we do this we also want to enable 'detect_prio', to ensure
we pick the correct prioritizer.

So this patch updates the default setting to always enable
'retain_hw_handler' and 'detect_prio' and switch to 'tur'
as the default path checker.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 libmultipath/checkers.h    | 2 +-
 libmultipath/defaults.h    | 4 ++--
 multipath/multipath.conf.5 | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/libmultipath/checkers.h b/libmultipath/checkers.h
index a935b3f..374c826 100644
--- a/libmultipath/checkers.h
+++ b/libmultipath/checkers.h
@@ -85,7 +85,7 @@ enum path_check_state {
 #define READSECTOR0  "readsector0"
 #define CCISS_TUR    "cciss_tur"
 
-#define DEFAULT_CHECKER DIRECTIO
+#define DEFAULT_CHECKER TUR
 
 #define ASYNC_TIMEOUT_SEC	30
 
diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
index 96f5a2c..4948271 100644
--- a/libmultipath/defaults.h
+++ b/libmultipath/defaults.h
@@ -16,8 +16,8 @@
 #define DEFAULT_FIND_MULTIPATHS	0
 #define DEFAULT_FAST_IO_FAIL	5
 #define DEFAULT_DEV_LOSS_TMO   600
-#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_OFF
-#define DEFAULT_DETECT_PRIO DETECT_PRIO_OFF
+#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_ON
+#define DEFAULT_DETECT_PRIO DETECT_PRIO_ON
 #define DEFAULT_DEFERRED_REMOVE DEFERRED_REMOVE_OFF
 #define DEFAULT_DELAY_CHECKS DELAY_CHECKS_OFF
 #define DEFAULT_UEVENT_STACKSIZE 256
diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
index aaaa01b..20a2304 100644
--- a/multipath/multipath.conf.5
+++ b/multipath/multipath.conf.5
@@ -295,7 +295,7 @@ Check the path state for LSI/Engenio/NetApp E-Series RDAC storage controller.
 .B directio
 Read the first sector with direct I/O.
 .TP
-Default value is \fIdirectio\fR.
+Default value is \fItur\fR.
 .RE
 .TP
 .B failback
@@ -463,7 +463,7 @@ are supported, or the
 prioritizer if not. If set to
 .I no
 , the prioritizer will be selected as usual. Default is
-.I no
+.I yes
 .TP
 .B force_sync
 If set to
-- 
2.6.6

Re: [PATCH] multipathd: update defaults

[Christophe Varoqui]

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Agreed.
Waiting for Ben's ack before merging.

On Fri, Jun 3, 2016 at 9:14 AM, Hannes Reinecke <hare@suse.de> wrote:

> For years I've been telling our customers to use the 'tur' checker
> as the current default 'directio' will cause spurious path failures
> under high load.
>
> And for several versions (years, even) the linux kernel has the ability
> to correctly detect the device handler, so we should be making
> 'retain_hw_handler' the default.
> And if we do this we also want to enable 'detect_prio', to ensure
> we pick the correct prioritizer.
>
> So this patch updates the default setting to always enable
> 'retain_hw_handler' and 'detect_prio' and switch to 'tur'
> as the default path checker.
>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  libmultipath/checkers.h    | 2 +-
>  libmultipath/defaults.h    | 4 ++--
>  multipath/multipath.conf.5 | 4 ++--
>  3 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/libmultipath/checkers.h b/libmultipath/checkers.h
> index a935b3f..374c826 100644
> --- a/libmultipath/checkers.h
> +++ b/libmultipath/checkers.h
> @@ -85,7 +85,7 @@ enum path_check_state {
>  #define READSECTOR0  "readsector0"
>  #define CCISS_TUR    "cciss_tur"
>
> -#define DEFAULT_CHECKER DIRECTIO
> +#define DEFAULT_CHECKER TUR
>
>  #define ASYNC_TIMEOUT_SEC      30
>
> diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
> index 96f5a2c..4948271 100644
> --- a/libmultipath/defaults.h
> +++ b/libmultipath/defaults.h
> @@ -16,8 +16,8 @@
>  #define DEFAULT_FIND_MULTIPATHS        0
>  #define DEFAULT_FAST_IO_FAIL   5
>  #define DEFAULT_DEV_LOSS_TMO   600
> -#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_OFF
> -#define DEFAULT_DETECT_PRIO DETECT_PRIO_OFF
> +#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_ON
> +#define DEFAULT_DETECT_PRIO DETECT_PRIO_ON
>  #define DEFAULT_DEFERRED_REMOVE DEFERRED_REMOVE_OFF
>  #define DEFAULT_DELAY_CHECKS DELAY_CHECKS_OFF
>  #define DEFAULT_UEVENT_STACKSIZE 256
> diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
> index aaaa01b..20a2304 100644
> --- a/multipath/multipath.conf.5
> +++ b/multipath/multipath.conf.5
> @@ -295,7 +295,7 @@ Check the path state for LSI/Engenio/NetApp E-Series
> RDAC storage controller.
>  .B directio
>  Read the first sector with direct I/O.
>  .TP
> -Default value is \fIdirectio\fR.
> +Default value is \fItur\fR.
>  .RE
>  .TP
>  .B failback
> @@ -463,7 +463,7 @@ are supported, or the
>  prioritizer if not. If set to
>  .I no
>  , the prioritizer will be selected as usual. Default is
> -.I no
> +.I yes
>  .TP
>  .B force_sync
>  If set to
> --
> 2.6.6
>
>

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Re: [PATCH] multipathd: update defaults

[Benjamin Marzinski]

On Fri, Jun 03, 2016 at 09:14:32AM +0200, Hannes Reinecke wrote:
> For years I've been telling our customers to use the 'tur' checker
> as the current default 'directio' will cause spurious path failures
> under high load.
> 
> And for several versions (years, even) the linux kernel has the ability
> to correctly detect the device handler, so we should be making
> 'retain_hw_handler' the default.
> And if we do this we also want to enable 'detect_prio', to ensure
> we pick the correct prioritizer.
> 
> So this patch updates the default setting to always enable
> 'retain_hw_handler' and 'detect_prio' and switch to 'tur'
> as the default path checker.

ACK

-Ben

> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  libmultipath/checkers.h    | 2 +-
>  libmultipath/defaults.h    | 4 ++--
>  multipath/multipath.conf.5 | 4 ++--
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/libmultipath/checkers.h b/libmultipath/checkers.h
> index a935b3f..374c826 100644
> --- a/libmultipath/checkers.h
> +++ b/libmultipath/checkers.h
> @@ -85,7 +85,7 @@ enum path_check_state {
>  #define READSECTOR0  "readsector0"
>  #define CCISS_TUR    "cciss_tur"
>  
> -#define DEFAULT_CHECKER DIRECTIO
> +#define DEFAULT_CHECKER TUR
>  
>  #define ASYNC_TIMEOUT_SEC	30
>  
> diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
> index 96f5a2c..4948271 100644
> --- a/libmultipath/defaults.h
> +++ b/libmultipath/defaults.h
> @@ -16,8 +16,8 @@
>  #define DEFAULT_FIND_MULTIPATHS	0
>  #define DEFAULT_FAST_IO_FAIL	5
>  #define DEFAULT_DEV_LOSS_TMO   600
> -#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_OFF
> -#define DEFAULT_DETECT_PRIO DETECT_PRIO_OFF
> +#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_ON
> +#define DEFAULT_DETECT_PRIO DETECT_PRIO_ON
>  #define DEFAULT_DEFERRED_REMOVE DEFERRED_REMOVE_OFF
>  #define DEFAULT_DELAY_CHECKS DELAY_CHECKS_OFF
>  #define DEFAULT_UEVENT_STACKSIZE 256
> diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
> index aaaa01b..20a2304 100644
> --- a/multipath/multipath.conf.5
> +++ b/multipath/multipath.conf.5
> @@ -295,7 +295,7 @@ Check the path state for LSI/Engenio/NetApp E-Series RDAC storage controller.
>  .B directio
>  Read the first sector with direct I/O.
>  .TP
> -Default value is \fIdirectio\fR.
> +Default value is \fItur\fR.
>  .RE
>  .TP
>  .B failback
> @@ -463,7 +463,7 @@ are supported, or the
>  prioritizer if not. If set to
>  .I no
>  , the prioritizer will be selected as usual. Default is
> -.I no
> +.I yes
>  .TP
>  .B force_sync
>  If set to
> -- 
> 2.6.6
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

Re: [PATCH] multipathd: update defaults

[Xose Vazquez Perez]

Hannes Reinecke wrote:

> For years I've been telling our customers to use the 'tur' checker
> as the current default 'directio' will cause spurious path failures
> under high load.

If directio is unreliable, it must be _fixed_ or *removed* .
And this text in multipath.conf.5 needs to be replaced:
"readsector0 (Deprecated) Read the first sector of the device.
This checker is being deprecated, please use directio instead"

There are 11 devices with path_checker=directio as default option,
what to do with them ?

> And for several versions (years, even) the linux kernel has the ability
> to correctly detect the device handler, so we should be making
> 'retain_hw_handler' the default.
> And if we do this we also want to enable 'detect_prio', to ensure
> we pick the correct prioritizer.

I do really like both features, it makes the multipath setup almost
a completely unattended task. And neat for live_cd, installers of
distributions, rescue environments and anywhere with a ro /etc.

There are a handful of devices with prio=alua as default option,
and they should be revoked to their "original" configuration.

> So this patch updates the default setting to always enable
> 'retain_hw_handler' and 'detect_prio' and switch to 'tur'
> as the default path checker.

The patch should be split in two: directio->tur and autodetect_alua.

CCed: All controllers maintainers, let's see what they think.

> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  libmultipath/checkers.h    | 2 +-
>  libmultipath/defaults.h    | 4 ++--
>  multipath/multipath.conf.5 | 4 ++--
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/libmultipath/checkers.h b/libmultipath/checkers.h
> index a935b3f..374c826 100644
> --- a/libmultipath/checkers.h
> +++ b/libmultipath/checkers.h
> @@ -85,7 +85,7 @@ enum path_check_state {
>  #define READSECTOR0  "readsector0"
>  #define CCISS_TUR    "cciss_tur"
>  
> -#define DEFAULT_CHECKER DIRECTIO
> +#define DEFAULT_CHECKER TUR
>  
>  #define ASYNC_TIMEOUT_SEC	30
>  
> diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
> index 96f5a2c..4948271 100644
> --- a/libmultipath/defaults.h
> +++ b/libmultipath/defaults.h
> @@ -16,8 +16,8 @@
>  #define DEFAULT_FIND_MULTIPATHS	0
>  #define DEFAULT_FAST_IO_FAIL	5
>  #define DEFAULT_DEV_LOSS_TMO   600
> -#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_OFF
> -#define DEFAULT_DETECT_PRIO DETECT_PRIO_OFF
> +#define DEFAULT_RETAIN_HWHANDLER RETAIN_HWHANDLER_ON
> +#define DEFAULT_DETECT_PRIO DETECT_PRIO_ON
>  #define DEFAULT_DEFERRED_REMOVE DEFERRED_REMOVE_OFF
>  #define DEFAULT_DELAY_CHECKS DELAY_CHECKS_OFF
>  #define DEFAULT_UEVENT_STACKSIZE 256
> diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
> index aaaa01b..20a2304 100644
> --- a/multipath/multipath.conf.5
> +++ b/multipath/multipath.conf.5
> @@ -295,7 +295,7 @@ Check the path state for LSI/Engenio/NetApp E-Series RDAC storage controller.
>  .B directio
>  Read the first sector with direct I/O.
>  .TP
> -Default value is \fIdirectio\fR.
> +Default value is \fItur\fR.
>  .RE
>  .TP
>  .B failback
> @@ -463,7 +463,7 @@ are supported, or the
>  prioritizer if not. If set to
>  .I no
>  , the prioritizer will be selected as usual. Default is
> -.I no
> +.I yes
>  .TP
>  .B force_sync
>  If set to
> -- 
> 2.6.6