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From: NeilBrown <neilb@suse.de>
To: patrik@dsl.sk
Cc: linux-raid@vger.kernel.org
Subject: Re: Data offset
Date: Fri, 16 May 2014 08:07:46 +1000	[thread overview]
Message-ID: <20140516080746.74daa4ca@notabene.brown> (raw)
In-Reply-To: <CAAOsTSmQUzup9Oy1EZstEi-bqZPgYhuhT6upQsoEc7TXq7n3kg@mail.gmail.com>

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On Thu, 15 May 2014 16:11:46 +0200 Patrik Horník <patrik@dsl.sk> wrote:

> Hello,
> 
> I have couple of questions regarding data offset:
> 
> - Current mdadm sets 128 MiB offset apparently for reshaping backup
> file. Is it really used by reshape? From which kernel / mdadm version?

Yes.  Linux 3.5 or there abouts.  mdadm 3.3
> 
> - Is there any other good reason for such big offset?

No.  But when you typically have a terabyte of more per disc, 128MB isn't
very much.

> 
> - Is there a support for specifying data offset when creating array?
> In which version of mdadm? What are recommended lower values?

Yes. mdadm-3.3.  Recommended value is the default.  Lowest usable value is
the lowest value it will let you use.

Why does a 128MB offset bother you?

NeilBrown

> 
> Thanks.
> 
> Patrik
> --
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  reply	other threads:[~2014-05-15 22:07 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-15 14:11 Data offset Patrik Horník
2014-05-15 22:07 ` NeilBrown [this message]
2014-05-16  0:41   ` Patrik Horník
  -- strict thread matches above, loose matches on Subject: below --
2012-06-01 23:22 Data Offset freeone3000
2012-06-01 23:52 ` NeilBrown
2012-06-02  0:48   ` freeone3000
2012-06-04  3:35     ` NeilBrown
2012-06-04 18:26       ` Pierre Beck
2012-06-04 22:57         ` NeilBrown
2012-06-05  5:26           ` freeone3000
2012-06-05  5:44             ` NeilBrown
     [not found]               ` <CAFhY2CiDTMRSV2wFCMhT9ZstUkHkJS7E0p7SP-ssfqwaquo+0w@mail.gmail.com>
     [not found]                 ` <20120610074531.65eaed81@notabene.brown>
     [not found]                   ` <CAFhY2CgxkjH6JvJzvQt9XT0oawntK7YoTFqnXQJGzvqthD8XpQ@mail.gmail.com>
2012-06-13  9:46                     ` Pierre Beck
2012-06-13 12:49                       ` Phil Turmel
2012-06-13 17:56                         ` Pierre Beck
2012-06-13 18:11                           ` Phil Turmel
2012-06-13 18:22                             ` Pierre Beck
2012-06-13 18:49                               ` Piergiorgio Sartor
2012-06-20  3:56                                 ` freeone3000
2012-06-20 14:09                                   ` Pierre Beck
2012-06-25  6:25                                   ` NeilBrown
2014-02-24 11:22           ` wiebittewas
2014-02-24 21:38             ` NeilBrown
2012-05-10 17:42 Piergiorgio Sartor
2012-05-24  5:20 ` NeilBrown

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