Hello,
I am using CentOS Release 5.5, facing a problem on operating system level. Unable to create any file, giving me error read only file system. My / file system seems to be in read only mode. Also unable to list any directory or file in / mount point, but directory is available.

[root@etisalcom /]# ll
total 0

[root@etisalcom /]# cd /u01
[root@etisalcom u01]# pwd
/u01

[root@etisalcom cache]# touch abc.txt
touch: cannot touch `abc.txt': Read-only file system

[root@etisalcom cache]# mkdir abc
-bash: mkdir: command not found


[root@etisalcom cache]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
64Z 64Z 26G 100% /


[root@etisalcom cache]# df -i
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/mapper/VolGroup00-LogVol00
0 -33616300 33616300 - /

[root@etisalcom u01]# more /etc/fstab
/dev/VolGroup00/LogVol00 / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/VolGroup00/LogVol01 swap swap defaults 0 0
u01 /u02 ext3 defaults 0 0
/dev/cciss/c0d1p5 /u02 ext3 defaults 0 0


Thanks
Zeeshan

check cat /proc/mounts
rootfs is rw

also df -i out shown inodes are full if this happen then you need to add more space or remove unwanted files

[root@etisalcom trace]# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 ro,data=ordered 0 0
/dev /dev tmpfs rw 0 0
/proc /proc proc rw 0 0
/sys /sys sysfs rw 0 0
/proc/bus/usb /proc/bus/usb usbfs rw 0 0
devpts /dev/pts devpts rw 0 0
/dev/cciss/c0d0p1 /boot ext3 rw,data=ordered 0 0
tmpfs /dev/shm tmpfs rw 0 0
/dev/cciss/c0d1p5 /u02 ext3 rw,data=ordered 0 0
none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0
sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw 0 0
/etc/auto.misc /misc autofs rw,fd=7,pgrp=3264,timeout=300,minproto=5,maxproto=5,indirect 0 0
-hosts /net autofs rw,fd=13,pgrp=3264,timeout=300,minproto=5,maxproto=5,indirect 0 0
//10.168.20.169/Backups /u01/backup/windows_shared cifs rw,mand,unc=\\10.168.20.169\Backups,username=billing_backup,uid=0,noforceuid,gid=0,noforcegid,addr=1 0.168.20.169,file_mode=02767,dir_mode=0777,rsize=16384,wsize=57344 0 0

i have use fsck command with below options and reboot the machine, after reboot system got stuck, it give me error ext3-fs: corrupt root inode, run e2fsckw

Inode 10013579, i_blocks is 360, should be 352. Fix<y>? yes

Inode 10013580, i_blocks is 256, should be 248. Fix<y>? yes

Inode 10013581, i_blocks is 352, should be 344. Fix<y>? yes

Inode 10013582, i_blocks is 224, should be 216. Fix<y>? yes

Inode 10013583, i_blocks is 240, should be 232. Fix<y>?

/dev/VolGroup00/LogVol00: e2fsck canceled.

/dev/VolGroup00/LogVol00: ***** FILE SYSTEM WAS MODIFIED *****
/dev/VolGroup00/LogVol00: ***** REBOOT LINUX *****

/dev/VolGroup00/LogVol00: ********** WARNING: Filesystem still has errors **********

Thanks
Zeeshan

/dev/root / ext3 ro,data=ordered 0 0

it mean the / earlier before reboot in read only

Now boot server from cd Then try
#pvs
#pvscan,
#vgs
#vgscan
#lvs
#lvscan.

Then fsck every lvol and reboot it & check .