[CentOS] File system goes read-only once in a while

Mon Aug 4 09:25:49 UTC 2008
Mufit Eribol <hme at onart.com.tr>

Toby Bluhm wrote:
> Mufit Eribol wrote:
>> I have a LV on RAID mounted as /mnt/raid. Then /mnt/raid/var is 
>> symlinked to /var. 
> I was afraid you were going to say that.
> Go back to single user mode.
> mkdir /new_var
> cd /mnt/raid/var
> tar cf - . | ( cd /new_var ; tar xvf - )
> Make sure both dirs look the same.
> Change the link to /new_var. Or remove the old link & mv /new_var /var.
> reboot.
Toby, Thank you for this nice tip. It worked perfectly. The server is 
back in the game again.

Just for my learning experience, I would appreciate if you clarify one 
point though. Why are you afraid when you hear /mnt/raid/var symlinked 
to /var? Is something wrong with it?

Here is my fstab:
/dev/md2                /                       ext3    defaults        
1 1   <--- md2 Software RAID1
/dev/md1                /boot                   ext3    defaults        
1 2   <--- md0 Software RAID1
/dev/md0                /tmp                    ext3    defaults        
1 2   <--- md1 Software RAID1
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
LABEL=SWAP-sda3         swap                    swap    defaults,pri=1  0 0
LABEL=SWAP-sdb3         swap                    swap    defaults,pri=1  0 0
/dev/raid_vg0/raid_lv0  /mnt/raid               ext3    defaults        
0 0   <--- Hardware RAID10

Before, home and var were under /mnt/raid directory and symlinked to 
/home and /var. Now, both directories were copied to / (md2 software 
RAID1) as new_home and new_var and /home and /var symlinks are now 
pointing to these new directories. /mnt/raid (hardware RAID10) which is 
the main storage of my server is not being used at the moment.

I am planning to have 2 logical volumes (for home and var separately) 
instead of 1. Then, they will be mounted as separate partitions as /home 
and /var to /dev/raid_vg0/raid_lv0 and /dev/raid_vg0/raid_lv1, 
respectively. Is it a good approach? Please advise.

Thank you again.