linux-bcache.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Kent Overstreet <koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: James Harper <james.harper-NMzNsA1hOHcW+bLBXbPJGg@public.gmane.org>
Cc: "linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: grub and bcache
Date: Mon, 13 Aug 2012 14:26:27 -0700	[thread overview]
Message-ID: <20120813212627.GB6887@google.com> (raw)
In-Reply-To: <6035A0D088A63A46850C3988ED045A4B299F5324-mzsoxcrO4/2UD0RQwgcqbDSf8X3wrgjD@public.gmane.org>

On Sun, Aug 12, 2012 at 11:17:39AM +0000, James Harper wrote:
> Is the underlying bdev bcache format such that bios/grub won't be able to boot off it?

Bios isn't an issue, because the mbr just takes up the first 512 bytes
of the hard drive and bcache leaves the first 4k of the device unused.
But grub needs to be able to read everything, and it doesn't know
anything about bcache devices.

> 
> Or to put it another way, I am wondering whether I can get away with:
> 
> /dev/sd[ab]
>  md0
>   bcache
>    lvm
>     lv-root
>     lv-boot
> 
> like I do now without bcache and have grub find the lv-boot, or if I need a separate md device to hold /boot like:

Yeah, this is the one you'll need.

> 
> /dev/sd[ab]
>   md0
>     boot
>   md1
>     bcache
>       lvm
>         lv-root
>         lv-boot
> 
> thanks
> 
> James
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

      parent reply	other threads:[~2012-08-13 21:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-12 11:17 grub and bcache James Harper
     [not found] ` <6035A0D088A63A46850C3988ED045A4B299F5324-mzsoxcrO4/2UD0RQwgcqbDSf8X3wrgjD@public.gmane.org>
2012-08-13 21:26   ` Kent Overstreet [this message]

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=20120813212627.GB6887@google.com \
    --to=koverstreet-hpiqsd4aklfqt0dzr+alfa@public.gmane.org \
    --cc=james.harper-NMzNsA1hOHcW+bLBXbPJGg@public.gmane.org \
    --cc=linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).