From: "amit.sahrawat83@gmail.com" <amit.sahrawat83@gmail.com>
To: "hch@infradead.org" <hch@infradead.org>,
"david@fromorbit.com" <david@fromorbit.com>,
"xfs@oss.sgi.com" <xfs@oss.sgi.com>
Subject: Preallocation with direct IO?
Date: Thu, 29 Dec 2011 13:10:49 +0000 [thread overview]
Message-ID: <4efc665b.d139e30a.2f32.fffff97a@mx.google.com> (raw)
Hi,
I am using a test setup which is doing write using multiple threads using direct IO. The buffer size which is used to write is 512KB.
After continously running this for long duration - i observe that number of extents in each file is getting huge(2K..4K..). I observed that each extent is of 512KB(aligned to write buffer size). I wish to have low number of extents(i.e, reduce fragmentation)... In case of buffered IO- preallocation works good alongwith the mount option 'allocsize'. Is there anything which can be done for Direct IO?
Please advice for reducing fragmentation with direct IO.
Thanks & Regards,
Amit Sahrawat
Sent from my Nokia phone
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next reply other threads:[~2011-12-29 13:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-29 13:10 amit.sahrawat83 [this message]
2011-12-29 20:57 ` Preallocation with direct IO? Dave Chinner
2011-12-30 3:07 ` Amit Sahrawat
2011-12-30 20:43 ` Dave Chinner
2011-12-31 12:46 ` Amit Sahrawat
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