From: Eric Sandeen Subject: Re: >16TB issues Date: Tue, 21 Jul 2009 13:57:05 -0500 Message-ID: <4A660F81.5000509@redhat.com> References: <150c16850907021523p25ddae32v2eeea54418d2e6d5@mail.gmail.com> <20090703143729.GJ20343@webber.adilger.int> <150c16850907161104j5e059baep988c5f04a0552c8c@mail.gmail.com> <20090721161018.GH4231@webber.adilger.int> <150c16850907211152y3136aadx6ce42a8535a6ed61@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Andreas Dilger , linux-ext4@vger.kernel.org To: Justin Maggard Return-path: Received: from mx2.redhat.com ([66.187.237.31]:36026 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753107AbZGUS5J (ORCPT ); Tue, 21 Jul 2009 14:57:09 -0400 In-Reply-To: <150c16850907211152y3136aadx6ce42a8535a6ed61@mail.gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Justin Maggard wrote: > On Tue, Jul 21, 2009 at 9:10 AM, Andreas Dilger wrote: >>> Error reading block 576192512 (Attempt to read block from filesystem >>> resulted in short read) while reading inode and block bitmaps. Ignore >>> error? no >>> >>> e2fsck: Can't read an block bitmap while retrying to read bitmaps for /dev/md2 >>> e2fsck: aborted >> What is very strange here is that the block numbers being reported as >> having read errors are not even beyond the 16TB limit. Assuming 4kB blocks: >> >> 576192512 * 4kB = 2304770048kB = 2198GB >> >> Are there error messages in syslog/dmesg when this happens? > > No, no error messages from the kernel. But your llverdev utility > ended up showing problems on the device. After asking around on the > MD mailing list, that was apparently because of the page cache index > limit (at the time I was using a 32-bit kernel). > > Switching to a 64-bit kernel allowed me to pass the llverdev test and > get much further with a very large filesystem, but I'm running into > other issues now. I wrote up a very simple script to write 2TB files > onto the filesystem until the device fills up. It was able to write > ~16TB, but after that it ran into some problems. My kernel log now > has lots of messages like these: > EXT4-fs error (device md2): ext4_mb_generate_buddy: EXT4-fs: group > 163548: 32744 blocks in bitmap, 32768 in gd > - and - > EXT4-fs error (device md2): ext4_mb_mark_diskspace_used: Allocating > block 4294967391 in system zone of 131072 group > > I shouldn't need e2fsprogs to be compiled 64-bit as well, right? > Currently I've got a 64-bit kernel with 32-bit userspace. It -should- work but it is probably more bug-prone if "unsigned longs" still lurk. -Eric