From: Milan Broz <mbroz@redhat.com>
To: Peter Smith <peter.smith3882100@gmail.com>
Cc: dm-crypt@saout.de
Subject: Re: [dm-crypt] cryptsetup align problem
Date: Sun, 05 Sep 2010 12:07:38 +0200 [thread overview]
Message-ID: <4C836BEA.1030803@redhat.com> (raw)
In-Reply-To: <AANLkTinqJJT9ZOOQBeoYU8vQixcN5Q+huJmEWp38h7gu@mail.gmail.com>
On 09/04/2010 11:31 AM, Peter Smith wrote:
> I do not understand LVM well enough to say if it is correct or not
> regarding to metadatasize, but the reason why i am configuring it this
> way is a statement from Theodore Ts'o:
Teo's post is completely obsolete regarding default kvm metadata sizes.
Align cryptsetup to multiple of 1MiB
(2048 sectors in the cryptsetup) and you will have safe configuration.
If you do not understand LVM, please use most recent version and everything
will be aligned automatically.
It can be fine-tuned, but in most cases default is ok now.
(See "man pvcreate" --dataalignment if you want to force overwrite it.)
In lvm you can check alignment of PV with "pvs -o +pe_start --units k"
(If you have extent multiple of 512KiB then LVs are aligned automatically
even if fragmented - this is almost always true, default PE is 4M).
> The disk i am using has a erase block size on 512K, therefore my
> values is different.
1MiB is multiple of 512KiB so you are ok with above.
You do not need to align "to 512" but to "multiple of 512". Important
is that data start offset will start on erase block boundary.
Milan
next prev parent reply other threads:[~2010-09-05 10:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-25 21:50 [dm-crypt] cryptsetup align problem Peter Smith
2010-08-25 22:58 ` Milan Broz
2010-08-26 12:43 ` Peter Smith
2010-09-03 17:58 ` Christoph Anton Mitterer
2010-09-04 9:31 ` Peter Smith
2010-09-05 10:07 ` Milan Broz [this message]
2010-09-05 15:07 ` Peter Smith
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4C836BEA.1030803@redhat.com \
--to=mbroz@redhat.com \
--cc=dm-crypt@saout.de \
--cc=peter.smith3882100@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.