From owner-freebsd-geom@FreeBSD.ORG Wed Jan 7 03:06:00 2009 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 563EA106566B for ; Wed, 7 Jan 2009 03:06:00 +0000 (UTC) (envelope-from gcubfg-freebsd-geom@m.gmane.org) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.freebsd.org (Postfix) with ESMTP id CD9A28FC17 for ; Wed, 7 Jan 2009 03:05:59 +0000 (UTC) (envelope-from gcubfg-freebsd-geom@m.gmane.org) Received: from list by ciao.gmane.org with local (Exim 4.43) id 1LKOjw-0005aB-JV for freebsd-geom@freebsd.org; Wed, 07 Jan 2009 03:05:52 +0000 Received: from 78-1-183-240.adsl.net.t-com.hr ([78.1.183.240]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 07 Jan 2009 03:05:52 +0000 Received: from ivoras by 78-1-183-240.adsl.net.t-com.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 07 Jan 2009 03:05:52 +0000 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-geom@freebsd.org From: Ivan Voras Date: Wed, 07 Jan 2009 04:05:24 +0100 Lines: 44 Message-ID: References: <4AD370A6-2226-442F-BD80-8CFD4045B094@panasas.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig6C7F72843F284BBA96789D41" X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 78-1-183-240.adsl.net.t-com.hr User-Agent: Thunderbird 2.0.0.19 (Windows/20081209) In-Reply-To: <4AD370A6-2226-442F-BD80-8CFD4045B094@panasas.com> X-Enigmail-Version: 0.95.7 Sender: news Subject: Re: performance problem with gstripe X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Jan 2009 03:06:00 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig6C7F72843F284BBA96789D41 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Joel Jacobson wrote: > i have a bit of a weird issue, which i suspect is a configuration > problem, and was looking for a little advice. i have an LSI JBOD box > with a bunch of SAS drives that i would like to gstripe together. each= > drive individually seems to be able to do about 80 MB/sec streaming > write, and doing parallel dd's gives me the 160 MB/sec i would expect. = > if i gstripe them together with a 256k stripe width, i only see 80 > MB/sec, though. How do you measure this? If with dd, what block size (bs) do you use? >=20 > if, however, i newfs/mount it as ufs and then dd myself a big file, tha= t > gets me about 120-130 MB/sec. >=20 > why does mounting matter? I'd guess because of write caching that enables you to make use of multiple stripes at once, if your dd bs is smaller than 2*stripe size. --------------enig6C7F72843F284BBA96789D41 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAklkG/QACgkQldnAQVacBcgANwCgkIv2J0Q1IlVS7IpqWrhVCRH+ Q38AoLW+L3QE8L390yw02URRWyEM1ivc =66OT -----END PGP SIGNATURE----- --------------enig6C7F72843F284BBA96789D41--