Date: Fri, 30 Nov 2012 13:19:24 +0100 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-fs@freebsd.org Subject: Re: Performance Difference on UFS and ZFS Message-ID: <k9a88b$bqm$1@ger.gmane.org> In-Reply-To: <CAJOrxZCyshi0rBXpm__b4Qf6gw=fQe1EMsjnukRE-XKxa-_niw@mail.gmail.com> References: <CAJOrxZCNeo-v_=LT8x1UniRspzZ5qs_DnnOtnb4DnF-RwGFJFw@mail.gmail.com> <CAE-mSOLcc-USkCZqsiCFsp2SqJ7VPDdkkCHRCxP=8hSg=gAjdw@mail.gmail.com> <CAJOrxZCyshi0rBXpm__b4Qf6gw=fQe1EMsjnukRE-XKxa-_niw@mail.gmail.com>
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[-- Attachment #1 --] On 28/11/2012 16:54, Metin Döşlü wrote: > Hi Sergey, > > I tested it on a cc1.4xlarge EC2 instance, here is the specs: > > 23 GiB of memory > 33.5 EC2 Compute Units (2 x Intel Xeon X5570, quad-core “Nehalem” architecture) > 1690 GB of instance storage > 64-bit platform > > I installed PostgreSQL from its port on FreeBSD. I didn't do any > tuning for PostgreSQL or FreeBSD. Data access pattern consists of > completely from sequential reads such "select count(*) from > table_name". I measured performance with PostgreSQL's timing option. > As as side note; all queries are served from memory, so there were no > disk usage for these tests. As others said - this is interesting and unexpected. Are you sure everything is the same across benchmarks? Since you are running on a virtualized platform, it may be that other users of the same storage pool "steal" your IO performance. I did a benchmark with PostgreSQL and ZFS vs UFS a couple of years ago, and the conclusion was that, once tuned, the performance is very similar, with ZFS being slightly better. Since you are testing read-only sequential IO, can you run an alternative test with some other benchmark such as bonnie++? [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAlC4pE0ACgkQ/QjVBj3/HSx+qgCgpZww46FBjLWYL73V9e4sWqLT 72kAoJbjsHMDfoIoPVGD33huToD6HEjn =sgwp -----END PGP SIGNATURE-----
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