From: Roberto Spadim <roberto@spadim.com.br>
To: "Keld Jørn Simonsen" <keld@keldix.com>
Cc: Giovanni Tessore <giotex@texsoft.it>, linux-raid@vger.kernel.org
Subject: Re: md road-map: 2011
Date: Fri, 18 Feb 2011 17:22:31 -0200 [thread overview]
Message-ID: <AANLkTi=JsXwAVOi96aRVVwWnnJS0uPGMV+Fbi4u46G92@mail.gmail.com> (raw)
In-Reply-To: <20110218191820.GA2517@www2.open-std.org>
yeah, disk with badblock = disk with dynamic layout
i think with badblock we could port layout to all raid systems
(including raid1 hehe, i like raid1)
the area for badblock, we could clena then at startup with: write
000000, send TRIM command to sectors used by badblock area, this will
help disks with internal realloc functions (faster than md software)
2011/2/18 Keld Jørn Simonsen <keld@keldix.com>:
> On Fri, Feb 18, 2011 at 05:00:27PM -0200, Roberto Spadim wrote:
>> again... for realloc we need TRIM command or reserved sectors just for
>> bad block realloc, TRIM command tell MD what sector isn?t in use, at
>> WRITE command MD set the sector as inuse, at array creation md set
>> sector as inuse too. this will only work with ext4 and swap, others
>> filesystem don?t have TRIM. the solution of others filesystem are
>> based on not used block, but it?s a internal logic of each filesystem.
>> i don?t know what is best, TRIM command is nice (we can send TRIM to
>> disks, this help to make their life bigger) a bad block is a disk
>> getting smaller and smaller, the disk can realloc badblock. if it
>> cant, filesystem should realloc it (it have more information about
>> logic device, it shouldn?t, TRIM command is the information that disk
>> should have to discart blocks, not a filesystem logic, but... it?s a
>> option, filesystem can realloc)
>
> I think I prefer a realloc area in the raid metadata area. And the
> metadata area could be contaning a not-too-small realloc area, with an
> option of enlarging the realloc area at a later time. This could be done
> by shrinking the related file system, and then adding the freed space to
> the realloc area in the raid metadata.
>
> Some MBs set aside for this would not be noticeable in todays TB disks
> regime. I think current disk hardware allows relocation of under 1000
> blocks a 512 byte = under 512 kB. So no problem sizewise.
> Performance may be a bigger problem. Maybe some binary searcheable list
> built at MD RAID assembly time.
>
> best regards
> keld
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--
Roberto Spadim
Spadim Technology / SPAEmpresarial
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next prev parent reply other threads:[~2011-02-18 19:22 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-16 10:27 md road-map: 2011 NeilBrown
2011-02-16 11:28 ` Giovanni Tessore
2011-02-16 13:40 ` Roberto Spadim
2011-02-16 14:00 ` Robin Hill
2011-02-16 14:09 ` Roberto Spadim
2011-02-16 14:21 ` Roberto Spadim
2011-02-16 21:55 ` NeilBrown
2011-02-17 1:30 ` Roberto Spadim
2011-02-16 14:13 ` Joe Landman
2011-02-16 21:24 ` NeilBrown
2011-02-16 21:44 ` Roman Mamedov
2011-02-16 21:59 ` NeilBrown
2011-02-17 0:48 ` Phil Turmel
2011-02-16 22:12 ` Joe Landman
2011-02-16 15:42 ` David Brown
2011-02-16 21:35 ` NeilBrown
2011-02-16 22:34 ` David Brown
2011-02-16 23:01 ` NeilBrown
2011-02-17 0:30 ` David Brown
2011-02-17 0:55 ` NeilBrown
2011-02-17 1:04 ` Keld Jørn Simonsen
2011-02-17 10:45 ` David Brown
2011-02-17 10:58 ` Keld Jørn Simonsen
2011-02-17 11:45 ` Giovanni Tessore
2011-02-17 15:44 ` Keld Jørn Simonsen
2011-02-17 16:22 ` Roberto Spadim
2011-02-18 0:13 ` Giovanni Tessore
2011-02-18 2:56 ` Keld Jørn Simonsen
2011-02-18 4:27 ` Roberto Spadim
2011-02-18 9:47 ` Giovanni Tessore
2011-02-18 18:43 ` Keld Jørn Simonsen
2011-02-18 19:00 ` Roberto Spadim
2011-02-18 19:18 ` Keld Jørn Simonsen
2011-02-18 19:22 ` Roberto Spadim [this message]
2011-02-16 17:20 ` Joe Landman
2011-02-16 21:36 ` NeilBrown
2011-02-16 19:37 ` Phil Turmel
2011-02-16 21:44 ` NeilBrown
2011-02-17 0:11 ` Phil Turmel
2011-02-16 20:29 ` Piergiorgio Sartor
2011-02-16 21:48 ` NeilBrown
2011-02-16 22:53 ` Piergiorgio Sartor
2011-02-17 0:24 ` Phil Turmel
2011-02-17 0:52 ` NeilBrown
2011-02-17 1:14 ` Phil Turmel
2011-02-17 3:10 ` NeilBrown
2011-02-17 18:46 ` Phil Turmel
2011-02-17 21:04 ` Mr. James W. Laferriere
2011-02-18 1:48 ` NeilBrown
2011-02-17 19:56 ` Piergiorgio Sartor
2011-02-16 22:50 ` Keld Jørn Simonsen
2011-02-23 5:06 ` Daniel Reurich
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