All of lore.kernel.org
 help / color / mirror / Atom feed
From: Gregory Farnum <greg@gregs42.com>
To: Olivier Bonvalet <ceph.list@daevel.fr>
Cc: ceph-users <ceph-users@ceph.com>,
	"ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: [ceph-users] More writes on filestore than on journal ?
Date: Mon, 23 Mar 2015 07:29:05 -0700	[thread overview]
Message-ID: <CAC6JEv9J7jEtgv3tcruXr8TN6gXFn1_iNexv8S_F772MY2vjXw@mail.gmail.com> (raw)
In-Reply-To: <1427116891.16770.25.camel@daevel.fr>

On Mon, Mar 23, 2015 at 6:21 AM, Olivier Bonvalet <ceph.list@daevel.fr> wrote:
> Hi,
>
> I'm still trying to find why there is much more write operations on
> filestore since Emperor/Firefly than from Dumpling.

Do you have any history around this? It doesn't sound familiar,
although I bet it's because of the WBThrottle and flushing changes.

>
> So, I add monitoring of all perf counters values from OSD.
>
> From what I see : «filestore.ops» reports an average of 78 operations
> per seconds. But, block device monitoring reports an average of 113
> operations per seconds (+45%).
> please thoses 2 graphs :
> - https://daevel.fr/img/firefly/osd-70.filestore-ops.png
> - https://daevel.fr/img/firefly/osd-70.sda-ops.png

That's unfortunate but perhaps not surprising — any filestore op can
change a backing file (which requires hitting both the file and the
inode: potentially two disk seeks), as well as adding entries to the
leveldb instance.
-Greg

>
> Do you see what can explain this difference ? (this OSD use XFS)
>
> Thanks,
> Olivier
>
> _______________________________________________
> ceph-users mailing list
> ceph-users@lists.ceph.com
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

  parent reply	other threads:[~2015-03-23 14:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-23 13:21 More writes on filestore than on journal ? Olivier Bonvalet
     [not found] ` <1427116891.16770.25.camel-PaEMFeTk6C1QFI55V6+gNQ@public.gmane.org>
2015-03-23 13:22   ` More writes on blockdevice than on filestore ? Olivier Bonvalet
2015-03-23 14:29 ` Gregory Farnum [this message]
2015-03-23 14:35   ` [ceph-users] More writes on filestore than on journal ? Olivier Bonvalet

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=CAC6JEv9J7jEtgv3tcruXr8TN6gXFn1_iNexv8S_F772MY2vjXw@mail.gmail.com \
    --to=greg@gregs42.com \
    --cc=ceph-devel@vger.kernel.org \
    --cc=ceph-users@ceph.com \
    --cc=ceph.list@daevel.fr \
    /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.