From: Hannes Reinecke <hare@suse.de>
To: device-mapper development <dm-devel@redhat.com>
Subject: Re: [PATCH] [RFC] multipath: change the DEFAULT_MINIO for the request based multipath
Date: Thu, 20 Jan 2011 08:32:35 +0100 [thread overview]
Message-ID: <4D37E513.3070506@suse.de> (raw)
In-Reply-To: <91d6dae7d88296d8a1fe.1295472607@malahal>
On 01/19/2011 10:30 PM, Malahal Naineni wrote:
> The value of 1000 is good for bio based multipath. Seen 50% increase in
> I/O ops by setting it to 1 in request based multipath configuration.
> This patch would give poor performance for people still using the bio
> based multipath!
>
> Is it possible to detect request based multipath and change only for
> those configurations?
>
> diff -r e504a50b0db5 -r 91d6dae7d882 libmultipath/defaults.h
> --- a/libmultipath/defaults.h Wed Jan 19 13:16:40 2011 -0800
> +++ b/libmultipath/defaults.h Wed Jan 19 13:29:52 2011 -0800
> @@ -5,7 +5,7 @@
> #define DEFAULT_ALIAS_PREFIX "mpath"
> #define DEFAULT_FEATURES "0"
> #define DEFAULT_HWHANDLER "0"
> -#define DEFAULT_MINIO 1000
> +#define DEFAULT_MINIO 1
> #define DEFAULT_PGPOLICY FAILOVER
> #define DEFAULT_FAILBACK -FAILBACK_MANUAL
> #define DEFAULT_RR_WEIGHT RR_WEIGHT_NONE
>
Heh, that was the main reason for using request-based multipathing :-)
So yes, changing the behaviour is a good idea. But we should equally
be able to detect if request-based multipathing is present; maybe
we can key off the version number of dm-multipath?
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
next prev parent reply other threads:[~2011-01-20 7:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-19 21:30 [PATCH] [RFC] multipath: change the DEFAULT_MINIO for the request based multipath Malahal Naineni
2011-01-20 7:32 ` Hannes Reinecke [this message]
2011-01-20 16:07 ` Mike Snitzer
2011-01-21 7:03 ` Jun'ichi Nomura
2011-01-21 8:47 ` Christophe Varoqui
2011-01-21 14:12 ` Mike Snitzer
2011-01-21 14:46 ` Christophe Varoqui
2011-01-21 17:39 ` Malahal Naineni
2011-01-25 8:56 ` Jun'ichi Nomura
2011-01-26 2:23 ` Malahal Naineni
2011-01-26 17:27 ` nishant mungse
2011-01-27 15:16 ` nishant mungse
2011-01-31 23:53 ` Christophe Varoqui
2011-02-01 2:21 ` Malahal Naineni
2011-02-01 3:13 ` Mike Snitzer
2011-02-01 8:14 ` Malahal Naineni
2011-02-01 8:13 ` Malahal Naineni
2011-02-01 9:00 ` Christophe Varoqui
2011-02-01 9:51 ` Malahal Naineni
2011-01-21 13:26 ` Mike Snitzer
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