All of lore.kernel.org
 help / color / mirror / Atom feed
From: Spelic <spelic@shiftmail.org>
To: device-mapper development <dm-devel@redhat.com>
Subject: Does multipath require disabled write cache?
Date: Sun, 20 Jul 2014 23:20:07 +0200	[thread overview]
Message-ID: <53CC3287.3010708@shiftmail.org> (raw)

Hello all,
I am wondering if multipath requires a disabled write cache at the 
remote disks.
We have some external SAS disks, for which the connection is flaky and 
sometimes is lost and then they are detected again. Multipath seems 
perfect for this situation.
However, when the disks are lost, I suppose resets are issued, which 
might clear the write cache so that data located there might not be 
committed (true? well at least on power loss this is true).
It would be great if multipath would issue a flush every N  writes, and 
then remember the last N  writes and resubmit them when the path is 
reestablished, so that there is again chance to flush them to stable 
storage. (similar to DRBD epochs) However I don't know if this smart 
mechanism is implemented.

Thanks for info
S.

             reply	other threads:[~2014-07-20 21:20 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-20 21:20 Spelic [this message]
2014-07-21 17:49 ` Does multipath require disabled write cache? Mike Snitzer

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=53CC3287.3010708@shiftmail.org \
    --to=spelic@shiftmail.org \
    --cc=dm-devel@redhat.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.