RedHat6.3 64位系統，項目組安裝了Oracle數據庫，反饋查詢比較慢，嘗試關閉ext4文件系統的日誌功能。

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda3              95G   15G   75G  17% /
tmpfs                 7.8G   88K  7.8G   1% /dev/shm
/dev/sda1             388M   53M  315M  15% /boot
/dev/mapper/ora_vg-ora_lv1 97G  188M   92G   1% /u01
# mount
/dev/sda3 on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/mapper/ora_vg-ora_lv1 on /u01 type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

# blkid /dev/sda1
/dev/sda1: UUID="d1cc72e6-cea3-42bd-aa4a-de852d06561c" TYPE="ext4" 
# blkid /dev/sdb1
/dev/sdb1: UUID="fckJCG-fd3d-ZUXy-Jv2v-kWcl-2HAH-1TBaCb" TYPE="LVM2_member"

# dumpe2fs /dev/sda1        //正常
# dumpe2fs /dev/sdb1        //報錯
dumpe2fs 1.41.12 (17-May-2010)
dumpe2fs: Bad magic number in super-block while trying to open /dev/sdb1
Couldn‘t find valid filesystem superblock.

其中/dev/sda1是標準分區，/dev/sdb1是lvm的成員分區，應該使用以下方式查看

# dumpe2fs /dev/ora_vg/ora_lv1 | grep ‘Filesystem features‘ | grep ‘has_journal‘
dumpe2fs 1.41.12 (17-May-2010)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize

關閉ext4日誌功能

# tune2fs -O ^has_journal /dev/ora_vg/ora_lv1

本文出自 “一諾千金” 博客，請務必保留此出處http://hatech.blog.51cto.com/8360868/1967740

小記dump2fs，關閉ext4日誌功能