From: Ric Wheeler Subject: Re: large file system & high object count testing Date: Mon, 31 Aug 2009 13:02:24 -0400 Message-ID: <4A9C0220.1040503@redhat.com> References: <4A9BFB88.5030409@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, "Ted Ts'o" To: Ric Wheeler Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45390 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751046AbZHaRAz (ORCPT ); Mon, 31 Aug 2009 13:00:55 -0400 In-Reply-To: <4A9BFB88.5030409@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 08/31/2009 12:34 PM, Ric Wheeler wrote: > > We have put together a very large, relatively slow JBOD to test > scalability with (big server, 40GB of DRAM, 8 CPU's + 4 SAS expansion > shelves, each with 16 2TB WD S-ATA drives). > > In all, this is pulled together with DM (striped) to give us a bit > over 116TB. > > Testing was done on 2.6.31-rc6 along with the pu branches e2fsprogs. > > Everything went well until after the fsck - I think that I have > reproduced that earlier issue with a failed mount. > > mkfs took a very long time - longer than fsck. fsck (with around 500 > million 20KB files) finished in just under 2 hours. > > logs below, > > ric One more note - this file system was filled using fs_mark, but without doing any fsync() calls. The unmount took several minutes (which I did not time), but the following was logged during that: Mount: Aug 28 23:46:14 megadeth kernel: EXT4-fs (dm-75): barriers enabled Aug 28 23:46:14 megadeth kernel: EXT4-fs (dm-75): internal journal on dm-75:8 Aug 28 23:46:14 megadeth kernel: EXT4-fs (dm-75): delayed allocation enabled Aug 28 23:46:14 megadeth kernel: EXT4-fs: file extents enabled Aug 28 23:46:21 megadeth kernel: EXT4-fs: mballoc enabled Aug 28 23:46:21 megadeth kernel: EXT4-fs (dm-75): mounted filesystem with ordered data mode umount: Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 2580708130 blocks 516141626 reqs (511081408 success) Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 5060218 extents scanned, 0 goal hits, 5060218 2^N hits, 0 breaks, 0 lost Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 85164 generated and it took 471527376 Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 2590831616 preallocated, 10120312 discarded Mount after fsck: Aug 31 12:27:12 megadeth kernel: EXT4-fs (dm-75): ext4_check_descriptors: Checksum for group 487 failed (59799!=46827) Aug 31 12:27:12 megadeth kernel: EXT4-fs (dm-75): group descriptors corrupted! The MBALLOC messages are a bit worrying - what exactly gets discarded during an unmount? ric > > > [root@megadeth e2fsprogs]# time /sbin/mkfs.ext4 > /dev/vg_wdc_disks/lv_wdc_disks > mke2fs 1.41.8 (20-Jul-2009) > Filesystem label= > OS type: Linux > Block size=4096 (log=2) > Fragment size=4096 (log=2) > 4287627264 inodes, 31138512896 blocks > 1556925644 blocks (5.00%) reserved for the super user > First data block=0 > Maximum filesystem blocks=33285996544 > 950272 block groups > 32768 blocks per group, 32768 fragments per group > 4512 inodes per group > Superblock backups stored on blocks: > 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, > 2654208, > 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, > 102400000, 214990848, 512000000, 550731776, 644972544, 1934917632, > 2560000000, 3855122432, 5804752896, 12800000000, 17414258688, > 26985857024 > > Allocating group tables: done > Writing inode tables: done > Creating journal (32768 blocks): done > Writing superblocks and filesystem accounting information: done > > This filesystem will be automatically checked every 38 mounts or > 180 days, whichever comes first. Use tune2fs -c or -i to override. > > real 230m6.362s > user 2m30.844s > sys 200m1.002s > [root@megadeth e2fsprogs]# mount /dev/vg_wdc_disks/lv_wdc_disks /test_fs/ > [root@megadeth e2fsprogs]# df -H /test_fs/ > Filesystem Size Used Avail Use% Mounted on > /dev/mapper/vg_wdc_disks-lv_wdc_disks > 127T 256M 121T 1% /test_fs > > FSCK time: > > [root@megadeth e2fsck]# time ./e2fsck -f -tt > /dev/vg_wdc_disks/lv_wdc_disks > e2fsck 1.41.8 (20-Jul-2009) > Pass 1: Checking inodes, blocks, and sizes > Pass 1: Memory used: 1280k/18014398508273796k (1130k/151k), time: > 4630.05/780.40/3580.01 > Pass 1: I/O read: 126019MB, write: 0MB, rate: 27.22MB/s > Pass 2: Checking directory structure > Pass 2: Memory used: 1280k/18014398508921888k (65k/1216k), time: > 1215.10/454.21/705.79 > Pass 2: I/O read: 34221MB, write: 0MB, rate: 28.16MB/s > Pass 3: Checking directory connectivity > Peak memory: Memory used: 1280k/18014398509445284k (65k/1216k), time: > 5884.30/1263.59/4295.71 > Pass 3A: Memory used: 1280k/18014398509445284k (65k/1216k), time: > 0.00/ 0.00/ 0.00 > Pass 3A: I/O read: 0MB, write: 0MB, rate: 0.00MB/s > Pass 3: Memory used: 1280k/18014398508921888k (56k/1225k), time: > 1.49/ 0.33/ 1.14 > Pass 3: I/O read: 1MB, write: 0MB, rate: 0.67MB/s > Pass 4: Checking reference counts > Pass 4: Memory used: 1280k/724124k (56k/1225k), time: 91.59/89.70/ 1.88 > Pass 4: I/O read: 0MB, write: 0MB, rate: 0.00MB/s > Pass 5: Checking group summary information > Pass 5: Memory used: 312k/200728k (56k/257k), time: 685.24/170.49/73.72 > Pass 5: I/O read: 713MB, write: 0MB, rate: 1.04MB/s > /dev/vg_wdc_disks/lv_wdc_disks: 516142418/4287627264 files (0.0% > non-contiguous), 2859838991/31138512896 blocks > Memory used: 312k/200728k (56k/257k), time: 6679.27/1541.45/4371.67 > I/O read: 161012MB, write: 1MB, rate: 24.11MB/s > > real 112m14.925s > user 25m41.557s > sys 73m46.849s > > > REMOUNT: > > [root@megadeth e2fsck]# mount /dev/vg_wdc_disks/lv_wdc_disks /test_fs/ > mount: wrong fs type, bad option, bad superblock on > /dev/mapper/vg_wdc_disks-lv_wdc_disks, > missing codepage or helper program, or other error > In some cases useful info is found in syslog - try > dmesg | tail or so > > [root@megadeth ~]# tail -20 /var/log/messages > > Aug 31 12:27:12 megadeth kernel: EXT4-fs (dm-75): > ext4_check_descriptors: Checksum for group 487 failed (59799!=46827) > Aug 31 12:27:12 megadeth kernel: EXT4-fs (dm-75): group descriptors > corrupted! > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html