From: "Richard W.M. Jones" <rjones@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: Zdenek Kabelac <zkabelac@redhat.com>
Subject: Re: [linux-lvm] Testing the new LVM cache feature
Date: Thu, 22 May 2014 16:49:47 +0100 [thread overview]
Message-ID: <20140522154946.GD14236@redhat.com> (raw)
In-Reply-To: <20140522152232.GC14236@redhat.com>
It works once I use a single VG.
However the performance is exactly the same as the backing hard disk,
not the SDD. It seems I'm getting no benefit ...
# lvs
[...]
testoriginlv vg_guests Cwi-a-C--- 100.00g lv_cache [testoriginlv_corig]
# mount /dev/vg_guests/testoriginlv /tmp/mnt
# cd /tmp/mnt
# dd if=/dev/zero of=test.file bs=64K count=100000 oflag=direct
100000+0 records in
100000+0 records out
6553600000 bytes (6.6 GB) copied, 57.6301 s, 114 MB/s
# dd if=test.file of=/dev/zero bs=64K iflag=direct
100000+0 records in
100000+0 records out
6553600000 bytes (6.6 GB) copied, 47.6587 s, 138 MB/s
(Exactly the same numbers as when I tested the underlying HDD, and
about half the performance of the SDD.)
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html
next prev parent reply other threads:[~2014-05-22 15:49 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 [this message]
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
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
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=20140522154946.GD14236@redhat.com \
--to=rjones@redhat.com \
--cc=linux-lvm@redhat.com \
--cc=zkabelac@redhat.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).