From: Mark Nelson <mark.nelson@inktank.com>
To: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Cc: "ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: massive 4k random read drop with next branch
Date: Sun, 28 Apr 2013 07:24:10 -0500 [thread overview]
Message-ID: <517D14EA.7040002@inktank.com> (raw)
In-Reply-To: <FAEC0EE3-ECC3-4F94-8731-E14A6576F01E@profihost.ag>
On 04/28/2013 07:21 AM, Stefan Priebe - Profihost AG wrote:
> Am 27.04.2013 um 22:45 schrieb Mark Nelson <mark.nelson@inktank.com>:
>
>> On 04/27/2013 03:13 PM, Stefan Priebe wrote:
>>> Hello list,
>>>
>>> today i was testing next branch against bobtail using a testcluster. I
>>> upgraded this bobtail one to next branch.
>>>
>>> I used QEMU 1.4.1 with librdb (for next branch i applied josh writeback
>>> patch). My Testsystem had 5 Hosts with one OSD each and set replication
>>> to 2.
>>>
>>> All values where done with 8 jobs in parallel using fio in Qemu Guest.
>>>
>>> bobtail:
>>> rand 4k: write: io=164316KB, bw=1783KB/s, iops=445, runt= 92136msec
>>> rand 4k: read : io=1117MB, bw=12710KB/s, iops=3177, runt= 90028msec
>>> seq 4m: write: io=8588MB, bw=97233KB/s, iops=23, runt= 90444msec
>>> seq 4m: read : io=83616MB, bw=951227KB/s, iops=232, runt= 90013msec
>>>
>>> next branch:
>>> write: io=177236KB, bw=1963KB/s, iops=490, runt= 90284msec
>>> read : io=223628KB, bw=2408KB/s, iops=601, runt= 92875msec
>>> write: io=25936MB, bw=294443KB/s, iops=71, runt= 90199msec
>>> read : io=69856MB, bw=794585KB/s, iops=193, runt= 90025msec
>>
>> Was everything else the same between the tests? That does seem unusual. If it's easy for you to switch between bobtail and next, could you try some 4k rados bench read tests to see if it's also happening there?
>
> I think I got it. Under bobtail the whole stuff was in cache on the osd clients. While under next I tested while they were freshly rebooted ;-( sorry guys.
>
> Will retest.
No worries! Unless I'm explicitly testing from cache, I always do a
sync and drop_caches on both the clients and servers before doing any tests.
>
> Stefan
>>
>>>
>>> Greets,
>>> Stefan
>>>
>>> --
>>> 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
>>
next prev parent reply other threads:[~2013-04-28 12:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-27 20:13 massive 4k random read drop with next branch Stefan Priebe
2013-04-27 20:45 ` Mark Nelson
2013-04-28 12:21 ` Stefan Priebe - Profihost AG
2013-04-28 12:24 ` Mark Nelson [this message]
2013-04-27 21:14 ` Wido den Hollander
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=517D14EA.7040002@inktank.com \
--to=mark.nelson@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.