From: Xing Lin <xinglin@cs.utah.edu>
To: Gregory Farnum <greg@inktank.com>
Cc: "ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: When ceph synchronizes journal to disk?
Date: Mon, 04 Mar 2013 21:47:05 -0700 [thread overview]
Message-ID: <513578C9.4040602@cs.utah.edu> (raw)
In-Reply-To: <CAPYLRzhAfvXfnCi4qRtdPEnV+v1qUy+DVED2Z0eep7eTvG__BA@mail.gmail.com>
Maybe it is easier to tell in this way.
What we want to see is that the newly written data to stay in the
journal disk for as long as possible such that write workloads do not
compete for disk headers for read workloads. Any way to achieve that in
Ceph? Thanks,
Xing
On 03/04/2013 09:55 AM, Gregory Farnum wrote:
> The "journal [min|max] sync interval" values specify how frequently
> the OSD's "FileStore" sends a sync to the disk. However, data is still
> written into the normal filesystem as it comes in, and the normal
> filesystem continues to schedule normal dirty data writeouts. This is
> good — it means that when we do send a sync down you don't need to
> wait for all (30 seconds * 100MB/s) 3GB or whatever of data to go to
> disk before it's completed.
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prev parent reply other threads:[~2013-03-05 4:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-03 12:36 When ceph synchronizes journal to disk? Xing Lin
2013-03-04 16:32 ` Sage Weil
2013-03-05 4:08 ` Xing Lin
2013-03-04 16:55 ` Gregory Farnum
2013-03-05 4:33 ` Xing Lin
2013-03-05 8:37 ` When ceph synchronizes journal to disk? / read request Dieter Kasper
2013-03-05 20:13 ` Greg Farnum
2013-03-05 13:54 ` When ceph synchronizes journal to disk? Wido den Hollander
2013-03-05 20:12 ` Greg Farnum
2013-03-06 1:50 ` Xing Lin
2013-03-05 14:27 ` Ugis
2013-03-05 4:47 ` Xing Lin [this message]
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