From mboxrd@z Thu Jan 1 00:00:00 1970 From: jehan procaccia Subject: Re: howto downgrade ext4 to ext3 Date: Tue, 22 Sep 2009 17:31:06 +0200 Message-ID: <4AB8EDBA.1080108@it-sudparis.eu> References: <4AB39EC5.6070107@it-sudparis.eu> <20090918175851.GH26991@mit.edu> <4AB3D060.2020101@redhat.com> <20090918193456.GA27303@mit.edu> <4AB3F9C4.1010702@it-sudparis.eu> <20090918225834.GC28781@mit.edu> <4AB53F3E.4040007@it-sudparis.eu> <4AB581EF.7050701@redhat.com> Reply-To: jehan.procaccia@it-sudparis.eu Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Theodore Tso , linux-ext4@vger.kernel.org To: Eric Sandeen Return-path: Received: from smtp4.int-evry.fr ([157.159.10.71]:39266 "EHLO smtp4.int-evry.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753066AbZIVPbK (ORCPT ); Tue, 22 Sep 2009 11:31:10 -0400 In-Reply-To: <4AB581EF.7050701@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Eric Sandeen a =E9crit : > jehan procaccia wrote: >> Other inodes incriminated showed the same result -> over-quota . So=20 >> if user data finally cannot be written, after all ... quota wouldn't= =20 >> allow it anyway . > > The unfortunate thing in your situation though is that the user=20 > -thought- it did get written, just FYI. > > When quota is working properly, the denial is obvious up front. OK, indeed it's not fair for the users ! I had the time to experiment an ext4 FS mounted with -nodelalloc, and=20 now quotas seems to work fine with it ;-) . here's a test on a FS mounted with -nodelalloc while writing with dd for an amount of data between interval soft 300M=20 and hard 330M, it worked fine: [test@b03-05 ~]$ dd if=3D/dev/zero of=3D./big-101M.dd bs=3D1024 count=3D= 101000 103424000 octets (103 MB) copi=C3=A9s, 9,06256 s, 11,4 MB/s $ quota -s test /dev/mapper/VolGroup03S2IA-LogVolS2ia01 317M* 293M 323M 7days 1760 0 0 Then, user "test" writes another 100 Mb and fails as expected : [test@b03-05 ~]$ dd if=3D/dev/zero of=3D./big-102M.dd bs=3D1024 count=3D= 102000 dd: fermeture du fichier de sortie `./big-102M.dd': D=C3=A9bordement du= =20 quota d'espace disque $ quota -s test /dev/mapper/VolGroup03S2IA-LogVolS2ia01 323M* 293M 323M 6days 1761 0 0 [root@gizeh /disk00/test/test] $ ll big* -rw-r--r-- 1 test mci 103424000 Sep 21 11:11 big-101M.dd -rw-r--r-- 1 test mci 35729408 Sep 21 11:13 big-102M.dd however in terms of performances, it seriously drops (nearly 50% !) =20 with -nodelalloc on the NFS disk server, here's a simple local dd write= =20 test: ext4 -nodelalloc [root@gizeh /disk00] $ dd if=3D/dev/zero of=3D./big-300M.dd bs=3D1024 count=3D300000 307200000 bytes (307 MB) copied, 1.20125 seconds, 256 MB/s ext4 -delalloc [root@gizeh /disk01] $ dd if=3D/dev/zero of=3D./big-300M.dd bs=3D1024 count=3D300000 307200000 bytes (307 MB) copied, 0.752382 seconds, 408 MB/s however, the same test from an NFS workstation shows very small=20 differences between partition mounted with nodelalloc and delalloc: -nodealloc + NFS $ dd if=3D/dev/zero of=3D./big-100M.dd bs=3D1024 count=3D100000 102400000 octets (102 MB) copi=E9s, 9,09703 s, 11,3 MB/s delalloc + NFS $ dd if=3D/dev/zero of=3D./big-100M.dd bs=3D1024 count=3D100000 102400000 octets (102 MB) copi=E9s, 9,00392 s, 11,4 MB/s I supose that NFS is the bottleneck ! I will announce a maintenance on that server in order to remount my 12= =20 x 200GB partitions with -nodelalloc, if ever performances drops too muc= h=20 , then I'll probably choose to set quotas off until a redhat kernel=20 package provides a solution . does 2.6.31 already patche to deal correclty with delalloc and quotas ? Thanks . -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html