From: Neil Brown <neilb@suse.de>
To: ptb@inv.it.uc3m.es
Cc: linux raid <linux-raid@vger.kernel.org>
Subject: Re: asynchronous write
Date: Thu, 19 Jul 2007 21:41:14 +1000 [thread overview]
Message-ID: <18079.19930.835893.78600@notabene.brown> (raw)
In-Reply-To: message from Peter T. Breuer on Wednesday July 18
On Wednesday July 18, ptb@inv.it.uc3m.es wrote:
> Did the asynchronous write stuff (as it was in fr1) ever get into kernel
> software raid?
Hmmm... what was 'fr1' again??.. asks google.
http://www.it.uc3m.es/ptb/fr1/
Yes, that sound like the 'bitmap' support currently in md.
The bitmap is stored on disk which I think is different from what fr1
did.
Possibly having a volatile bitmap would be valuable. It would remove
the current extra cost of writes, and would still allow fast recovery
if you fail, then re-add a drive...
>
> I see from the raid acceleration ("ioat") patching going on that some
> sort of asynchronicity is being contemplated, but blessed if I can make
> head or tail of the descriptions I've read. It looks vaguely like
> purely memory-management stuff to me (what?) for external hardware raid,
> but what do I know ...
Yes. The ,'ioat' is for raid5/6 and allows the xor calculation,
memcpys and some other functions to be off-loaded to a co-processor.
NeilBrown
prev parent reply other threads:[~2007-07-19 11:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-18 8:24 asynchronous write Peter T. Breuer
2007-07-19 11:41 ` Neil Brown [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=18079.19930.835893.78600@notabene.brown \
--to=neilb@suse.de \
--cc=linux-raid@vger.kernel.org \
--cc=ptb@inv.it.uc3m.es \
/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.