[PATCH resend] multipath-tools: document why dev_loss_tmo is set to infinity for HPE 3PAR

[PATCH resend] multipath-tools: document why dev_loss_tmo is set to infinity for HPE 3PAR

[Xose Vazquez Perez]

It's needed by Peer Persistence, documented in SLES and RHEL guides:
https://support.hpe.com/hpsc/doc/public/display?docId=a00053835
https://support.hpe.com/hpsc/doc/public/display?docId=c04448818

Cc: Christophe Varoqui <christophe.varoqui@opensvc.com>
Cc: DM-DEVEL ML <dm-devel@redhat.com>
Signed-off-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
---
 libmultipath/hwtable.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libmultipath/hwtable.c b/libmultipath/hwtable.c
index d3a8d9b..543bacd 100644
--- a/libmultipath/hwtable.c
+++ b/libmultipath/hwtable.c
@@ -116,6 +116,7 @@ static struct hwentry default_hw[] = {
 		.prio_name     = PRIO_ALUA,
 		.no_path_retry = 18,
 		.fast_io_fail  = 10,
+		/* infinity is needed by Peer Persistence */
 		.dev_loss      = MAX_DEV_LOSS_TMO,
 	},
 	{
-- 
2.20.1

Re: [PATCH resend] multipath-tools: document why dev_loss_tmo is set to infinity for HPE 3PAR

[Martin Wilck]

On Sat, 2019-03-16 at 23:30 +0100, Xose Vazquez Perez wrote:
> It's needed by Peer Persistence, documented in SLES and RHEL guides:
> https://support.hpe.com/hpsc/doc/public/display?docId=a00053835
> https://support.hpe.com/hpsc/doc/public/display?docId=c04448818
> 
> Cc: Christophe Varoqui <christophe.varoqui@opensvc.com>
> Cc: DM-DEVEL ML <dm-devel@redhat.com>
> Signed-off-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
> ---
>  libmultipath/hwtable.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/libmultipath/hwtable.c b/libmultipath/hwtable.c
> index d3a8d9b..543bacd 100644
> --- a/libmultipath/hwtable.c
> +++ b/libmultipath/hwtable.c
> @@ -116,6 +116,7 @@ static struct hwentry default_hw[] = {
>  		.prio_name     = PRIO_ALUA,
>  		.no_path_retry = 18,
>  		.fast_io_fail  = 10,
> +		/* infinity is needed by Peer Persistence */
>  		.dev_loss      = MAX_DEV_LOSS_TMO,
>  	},
>  	{

I'm not quite getting the benefit of adding this comment without
further explanation what Peer Persistence is. Also, IMO, setting
dev_loss_tmo to a higher value than the default (contrary to lowering
it) doesn't require much justification.

But it can't really hurt, so:

Reviewed-by: Martin Wilck <mwilck@suse.com>