All of lore.kernel.org
 help / color / mirror / Atom feed
From: Josh Durgin <josh.durgin@inktank.com>
To: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Cc: "ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: difference between qemu cache settings and ceph.conf rbd cache settings?
Date: Mon, 18 Jun 2012 23:42:54 -0700	[thread overview]
Message-ID: <4FE01F6E.50200@inktank.com> (raw)
In-Reply-To: <4FE01E35.1080002@profihost.ag>

On 06/18/2012 11:37 PM, Stefan Priebe - Profihost AG wrote:
> Hello list,
>
> i've now patched my qemu to include the qemu cache settings for rbd.
>
> Now i can change my drive caching mode. But there are also these
> settings for global section in ceph.conf.
>
> rbd_cache = true
> rbd_cache_size = 33554432
> rbd_cache_max_age = 2.0
>
> How do they influence or replace each other?
>
> thanks
> Stefan

In qemu, the cache settings map to:

writeback:
   rbd_cache = true

writethrough:
   rbd_cache = true
   rbd_cache_max_dirty = 0

none:
   rbd_cache = false

qemu's settings are overridden by any custom settings you have in a
config file or on the qemu command line.

Josh

  reply	other threads:[~2012-06-19  6:42 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-19  6:37 difference between qemu cache settings and ceph.conf rbd cache settings? Stefan Priebe - Profihost AG
2012-06-19  6:42 ` Josh Durgin [this message]
2012-06-19  6:44   ` Stefan Priebe - Profihost AG

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=4FE01F6E.50200@inktank.com \
    --to=josh.durgin@inktank.com \
    --cc=ceph-devel@vger.kernel.org \
    --cc=s.priebe@profihost.ag \
    /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.