From: Kent Overstreet <koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: Roy Sigurd Karlsbakk <roy-ooPBL11mRiZbRRN4PJnoQQ@public.gmane.org>
Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Steven Haigh <netwiz-tY1ak9Q0PTWHXe+LvDLADg@public.gmane.org>
Subject: Re: Adding caching to existing volumes?
Date: Thu, 24 Jan 2013 13:21:03 -0800 [thread overview]
Message-ID: <20130124212103.GI26407@google.com> (raw)
In-Reply-To: <12410785.14.1358961464521.JavaMail.root@zimbra>
On Wed, Jan 23, 2013 at 06:17:44PM +0100, Roy Sigurd Karlsbakk wrote:
> > You've got to start from scratch, unfortunately.
> >
> > The reason is that there needs to be a bcache specific superblock on
> > the
> > backing device so bcache can keep the cache and backing device in sync
> > -
> > and especially so you can't accidentally mount and use the backing
> > device without the cache. That would be bad.
> >
> > I just added an explanation to the faq - thanks for pointing it out.
> > http://bcache.evilpiepirate.org/FAQ
>
> Then, what happens when the SSD dies?
Formatting a backing device for bcache is separate from attaching it to
a cache device - you can always run it in passthrough mode, and if the
SSD dies while it's in use it'll automatically/transparently detach and
switch to passthrough mode.
prev parent reply other threads:[~2013-01-24 21:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-19 18:08 Adding caching to existing volumes? Roy Sigurd Karlsbakk
2013-01-20 8:02 ` Steven Haigh
[not found] ` <50FBA4A6.7020709-tY1ak9Q0PTWHXe+LvDLADg@public.gmane.org>
2013-01-22 23:15 ` Kent Overstreet
[not found] ` <20130122231547.GF26407-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2013-01-22 23:26 ` Steven Haigh
[not found] ` <50FF2016.4020802-tY1ak9Q0PTWHXe+LvDLADg@public.gmane.org>
2013-01-22 23:42 ` James Harper
2013-01-23 17:17 ` Roy Sigurd Karlsbakk
2013-01-24 21:21 ` Kent Overstreet [this message]
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