From: Milan Broz <mbroz@redhat.com>
To: Sven Eschenberg <sven@whgl.uni-frankfurt.de>
Cc: dm-crypt@saout.de
Subject: Re: [dm-crypt] Wrong behavior?
Date: Wed, 14 Jul 2010 13:52:53 +0200 [thread overview]
Message-ID: <4C3DA515.4030909@redhat.com> (raw)
In-Reply-To: <1279107557.2415.3.camel@Koma-Station.localdomain>
On 07/14/2010 01:39 PM, Sven Eschenberg wrote:
> Is there any 'easy' way to access this information. specifically I am
> interested, why md would report a 6144 sectors alignment on my 4 disk
> raid5 with 512 kb chunks instead of 3072.
Values are in in sysfs also, I am just using topology ioctl which is simpler.
sysfs interface
---------------
/sys/block/<disk>/alignment_offset
/sys/block/<disk>/<partition>/alignment_offset
/sys/block/<disk>/queue/physical_block_size
/sys/block/<disk>/queue/logical_block_size
/sys/block/<disk>/queue/minimum_io_size
/sys/block/<disk>/queue/optimal_io_size
cryptsetup uses minimal/optimal io_size and alignment value
to calculate payload offset.
A lot of info here:
http://people.redhat.com/msnitzer/docs/io-limits.txt
https://ata.wiki.kernel.org/index.php/ATA_4_KiB_sector_issues
Milan
next prev parent reply other threads:[~2010-07-14 11:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-13 20:51 [dm-crypt] Wrong behavior? Sven Eschenberg
2010-07-13 21:12 ` Milan Broz
2010-07-13 22:17 ` Sven Eschenberg
[not found] ` <AANLkTilvdewwcdzdm2uX6go9q2dahLX7Fes-lwDNOkvU@mail.gmail.com>
2010-07-14 6:07 ` MkFly
2010-07-14 6:38 ` Heinz Diehl
2010-07-14 8:20 ` Milan Broz
2010-07-14 10:09 ` Arno Wagner
2010-07-14 18:09 ` Christoph Anton Mitterer
2010-07-14 7:58 ` Milan Broz
2010-07-14 11:39 ` Sven Eschenberg
2010-07-14 11:52 ` Milan Broz [this message]
2010-07-14 12:07 ` Sven Eschenberg
2010-07-14 12:13 ` Arno Wagner
2010-07-14 12:53 ` Milan Broz
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