From owner-freebsd-fs@FreeBSD.ORG Mon Jun 8 00:56:04 2009 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EA98C1065672 for ; Mon, 8 Jun 2009 00:56:04 +0000 (UTC) (envelope-from freebsd-fs@m.gmane.org) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.freebsd.org (Postfix) with ESMTP id 741FD8FC15 for ; Mon, 8 Jun 2009 00:56:04 +0000 (UTC) (envelope-from freebsd-fs@m.gmane.org) Received: from list by ciao.gmane.org with local (Exim 4.43) id 1MDT9f-00047z-42 for freebsd-fs@freebsd.org; Mon, 08 Jun 2009 00:56:03 +0000 Received: from 93-138-27-194.adsl.net.t-com.hr ([93.138.27.194]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 08 Jun 2009 00:56:03 +0000 Received: from ivoras by 93-138-27-194.adsl.net.t-com.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 08 Jun 2009 00:56:03 +0000 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-fs@freebsd.org From: Ivan Voras Date: Mon, 08 Jun 2009 02:55:22 +0200 Lines: 61 Message-ID: References: <4A2AA48B.20803@free.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig4E69E4FE3B573ADD3EAB6334" X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 93-138-27-194.adsl.net.t-com.hr User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) In-Reply-To: <4A2AA48B.20803@free.de> X-Enigmail-Version: 0.95.7 Sender: news Subject: Re: ZFS v13 performance drops with low memory on FreeBSD-7 STABLE X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Jun 2009 00:56:05 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig4E69E4FE3B573ADD3EAB6334 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Kai Gallasch wrote: > Hi. >=20 > I upgraded a server with 7-STABLE-amd64 and the MFC'd ZFS v13 about 8 > days ago. Since then the machine is running stable and this without > manually tuning vm.kmem_size, vfs.zfs.arc, etc. in loader.conf - so far= > so good :-) >=20 > In the last few days I noticed some performance issues with zfs, as som= e > customers complained about slow mysql database responses. >=20 > MySQL is running in a database jail on a zfs v13 zpool, websites using > the mysql database are also running on zfs on the same server. >=20 > The server is running about 30 in production jails, has 16GB RAM and 8G= B > swap. Swap usage is about only 1% currently. >=20 > After debugging the mysql settings for a while I found out, that when I= > stopped some processes on the server that were using high amounts of > RAM, the datbase response times for queries were almost back to normal > again.. >=20 > So for me this looks like when running applications and ZFS compete for= > free RAM, ZFS looses. Is that so? Yes, that was the point of recent work in stabilizing ZFS - without it you would probably panic. With it, ZFS's memory is shrunk down. Unless there are other factors (like swapping; are you swapping on ZFS?), this is the probable reason for what you're seeing. It's kind of bad when the file system competes this directly with applications :( --------------enig4E69E4FE3B573ADD3EAB6334 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 iEYEARECAAYFAkosYXsACgkQldnAQVacBcg9OACdEi0W0QMOvjtHmZoay/BCcITg YPcAoKs4+xEUNx7gZdTH82yXGHAoUJ/0 =IQah -----END PGP SIGNATURE----- --------------enig4E69E4FE3B573ADD3EAB6334--