Read-only file system
Once upon a time when I tried to create a folder using ftp client on the server, I get error "cant create directory gallery: read-only filesystem".
After googling a while I found the solution on Always Hosting Forum. And the only way to resolve it permanently is by running fsck utility on linux single mode before mounting the harddrive. Yes there is a temporarily solution by restarting the server, but when the system is about to write into failed inode it will freeze, daemons stop responding, connections rejected, etc to make sure it wont cause more broken inode will lead into data corruption.
Thanks God, after running fsck, all data still intact, I haven’t found corrupted/missing data (yet). Important lesson is when your system is hang, please try using soft-restart (init 6, shutdown -r) and not just pressing the Power button directly (hard-restart) which can cause data instability.
It’s a very hard lesson. 
