From: "Richard W.M. Jones" <rjones@redhat.com>
To: Mike Snitzer <snitzer@redhat.com>
Cc: Heinz Mauelshagen <heinzm@redhat.com>,
Zdenek Kabelac <zkabelac@redhat.com>,
thornber@redhat.com,
LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] Testing the new LVM cache feature
Date: Fri, 30 May 2014 14:46:42 +0100 [thread overview]
Message-ID: <20140530134642.GL1302@redhat.com> (raw)
In-Reply-To: <20140530133814.GB8830@redhat.com>
I have now set both read_promote_adjustment ==
write_promote_adjustment == 0 and used drop_caches between runs.
I also read Documentation/device-mapper/cache-policies.txt at Heinz's
suggestion.
I'm afraid the performance of the fio test is still not the same as
the SSD (4.8 times slower than the SSD-only test now).
Would repeated runs of (md5sum virt.* ; echo 3 > /proc/sys/vm/drop_caches)
not eventually cause the whole file to be placed on the SSD?
It does seem very counter-intuitive if not.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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next prev parent reply other threads:[~2014-05-30 13:46 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-22 10:18 [linux-lvm] Testing the new LVM cache feature Richard W.M. Jones
2014-05-22 14:43 ` Zdenek Kabelac
2014-05-22 15:22 ` Richard W.M. Jones
2014-05-22 15:49 ` Richard W.M. Jones
2014-05-22 18:04 ` Mike Snitzer
2014-05-22 18:13 ` Richard W.M. Jones
2014-05-29 13:52 ` Richard W.M. Jones
2014-05-29 20:34 ` Mike Snitzer
2014-05-29 20:47 ` Richard W.M. Jones
2014-05-29 21:06 ` Mike Snitzer
2014-05-29 21:19 ` Richard W.M. Jones
2014-05-29 21:58 ` Mike Snitzer
2014-05-30 9:04 ` Richard W.M. Jones
2014-05-30 10:30 ` Richard W.M. Jones
2014-05-30 13:38 ` Mike Snitzer
2014-05-30 13:40 ` Richard W.M. Jones
2014-05-30 13:42 ` Heinz Mauelshagen
2014-05-30 13:54 ` Richard W.M. Jones
2014-05-30 13:58 ` Zdenek Kabelac
2014-05-30 13:46 ` Richard W.M. Jones [this message]
2014-05-30 13:54 ` Heinz Mauelshagen
2014-05-30 14:26 ` Richard W.M. Jones
2014-05-30 14:29 ` Mike Snitzer
2014-05-30 14:36 ` Richard W.M. Jones
2014-05-30 14:44 ` Mike Snitzer
2014-05-30 14:51 ` Richard W.M. Jones
2014-05-30 14:58 ` Mike Snitzer
2014-05-30 15:28 ` Richard W.M. Jones
2014-05-30 18:16 ` Mike Snitzer
2014-05-30 20:53 ` Mike Snitzer
2014-05-30 13:55 ` Mike Snitzer
2014-05-30 14:29 ` Richard W.M. Jones
2014-05-30 14:36 ` Mike Snitzer
2014-05-30 11:53 ` Mike Snitzer
2014-05-30 11:38 ` Alasdair G Kergon
2014-05-30 11:45 ` Alasdair G Kergon
2014-05-30 12:45 ` Werner Gold
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