From: Milan Broz <mbroz@redhat.com>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] status of dm-crypt (alignment issues) on a SSD
Date: Thu, 02 Dec 2010 12:44:13 +0100 [thread overview]
Message-ID: <4CF7868D.4040404@redhat.com> (raw)
In-Reply-To: <20101202075413.GE19274@maude.comedia.it>
On 12/02/2010 08:54 AM, Luca Berra wrote:
> what you need on kernel side is having in sysfs
> under /sys/block/<device>
> queue/minimum_io_size
> queue/optimal_io_size
> queue/physical_block_size
Just not all SSD presents proper values here.
My advice is align to 1MiB in such case and it will work:-)
(this is default in recent versions - not all yet in Debian)
You can always do it manually, use fdisk -u (to work in sector mode,
note sector is 512B. Switch off DOS mode if it is enabled - there
should be warning)
For lvm, use pvcreate --dataalignment, then check with pvs -o +pe_start.
(You can use --units S to work in sectors mode like in fdisk.
2048 sectors == 1MiB, any multiple of it is ok)
(See man page and check archive, I think it was described here
several times.)
Milan
next prev parent reply other threads:[~2010-12-02 11:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-01 14:51 [dm-crypt] status of dm-crypt (alignment issues) on a SSD mike dentifrice
2010-12-02 7:54 ` Luca Berra
2010-12-02 11:44 ` Milan Broz [this message]
2010-12-02 11:50 ` mike dentifrice
2010-12-02 12:08 ` Milan Broz
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