From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o6QA9e7T113200 for ; Mon, 26 Jul 2010 05:09:41 -0500 Received: from piggy.rz.tu-ilmenau.de (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 9C438162A53E for ; Mon, 26 Jul 2010 03:12:43 -0700 (PDT) Received: from piggy.rz.tu-ilmenau.de (piggy.rz.tu-ilmenau.de [141.24.4.8]) by cuda.sgi.com with ESMTP id xuoMX7GlqminHLPr for ; Mon, 26 Jul 2010 03:12:43 -0700 (PDT) Received: from p4FD557E8.dip.t-dialin.net (vpn4.rz.tu-ilmenau.de [141.24.172.4]) by piggy.rz.tu-ilmenau.de (8.13.7/8.13.7/Debian-2) with ESMTP id o6QACdxe013493 for ; Mon, 26 Jul 2010 12:12:40 +0200 Received: from darkside.kls.lan (root@darkside.kls.lan [IPv6:2001:6f8:90c:12:21e:8cff:fecf:cfad]) by p4FD557E8.dip.t-dialin.net (8.14.3/8.14.3) with ESMTP id o6QACd2d026884 for ; Mon, 26 Jul 2010 12:12:40 +0200 Received: from darkside.kls.lan (holbe@localhost [IPv6:::1]) by darkside.kls.lan (8.14.3/8.14.3) with ESMTP id o6QACd4Q007738 for ; Mon, 26 Jul 2010 12:12:39 +0200 Received: (from holbe@localhost) by darkside.kls.lan (8.14.3/8.14.3) id o6QACdjR007736 for xfs@oss.sgi.com; Mon, 26 Jul 2010 12:12:39 +0200 Date: Mon, 26 Jul 2010 12:12:39 +0200 From: "Mario 'BitKoenig' Holbe" Subject: mkfs.xfs: cannot (re)set log sunit=0 Message-ID: <20100726101238.GA7725@darkside.kls.lan> MIME-Version: 1.0 List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============3608643855679432494==" Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com --===============3608643855679432494== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="jRHKVT23PllUwdXP" Content-Disposition: inline --jRHKVT23PllUwdXP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello, I intend to set up a XFS filesystem on a RAID0 (Linux md) with 512k Chunk Size. Since I cannot align the log section sunit to 512k, and since the filesystem will have not much write activity anyways (in fact, it'll be mounted read-only most of the time), I tried not to align the log section sunit at all via -l sunit=3D0, but this does not appear to work: # truncate -s 1G /tmp/foo{0,1} # losetup /dev/loop0 /tmp/foo0; losetup /dev/loop1 /tmp/foo1 # mdadm -C -l raid0 -n 2 /dev/md9 /dev/loop[01] # mkfs.xfs -l sunit=3D0 /dev/md9 log stripe unit (524288 bytes) is too large (maximum is 256KiB) log stripe unit adjusted to 32KiB meta-data=3D/dev/md9 isize=3D256 agcount=3D8, agsize=3D654= 08 blks =3D sectsz=3D512 attr=3D2 data =3D bsize=3D4096 blocks=3D523264, imaxpct= =3D25 =3D sunit=3D128 swidth=3D256 blks naming =3Dversion 2 bsize=3D4096 ascii-ci=3D0 log =3Dinternal log bsize=3D4096 blocks=3D2560, version=3D2 =3D sectsz=3D512 sunit=3D8 blks, lazy-coun= t=3D1 realtime =3Dnone extsz=3D4096 blocks=3D0, rtextents=3D0 Is this a bug or a feature? The minimum I was able to limit the log sunit to was -l sunit=3D8, i.e. 1 block. Is there a difference between sunit=3D0 and sunit=3D1 in practice or are single log entries aligned to blocks anyways? Btw... Since the filesystem is mostly read-only, I was also thinking about reducing the size of the log section. The planned filesystem will be 5.5T or bigger, which results in 2G log section per default. I thought about limiting it to 128M or 64M. There will be no concurrent write activity on the fs. Together with the zero-alignment, what do you think about that? PS: I'm not on this list, please CC: me in replies. My Mail-Followup-To: header should take care of that. Thanks for your help & regards Mario --=20 File names are infinite in length where infinity is set to 255 characters. -- Peter Collinson, "The Unix File System" --jRHKVT23PllUwdXP Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEVAwUBTE1flhS+e2HeSPbpAQIcywgAjfMGyL36H2lv0Cp67exQHGtjkq1J2zGV Jk+2ZzXCyoZc2tnTSu+1LQ7cKRxr8LNgfSqBzWCRaGHGAgmhfeLRYjcDWx2vtu3D ilRTFydb8cRJlf96LmMyHZQi7Iz/TVWYK5gctkX74JM/KRI5VeyEZcIDW8DyN+wf 2BN+kt2qXLO2helMYrZo9vQ0Bc3Oxr+V3NJeRzdZ0OhwrB5/Cwn2zqHghP+FdMd9 nLj7PDYyNo2dGdHIb55EJz45J+NwIM1NIciN5kMYeKPwE4jEE0SmMD+UINvYnNAu 918J1SlYmpkrqtdXk8yg5k2IxMg5ZfzSyT+sPgZlx16T3rube1+h/Q== =FFAD -----END PGP SIGNATURE----- --jRHKVT23PllUwdXP-- --===============3608643855679432494== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs --===============3608643855679432494==--