The FC10 ext2 experiment has ended -- don't try this

[Bill Davidsen]

Robert Moskowitz wrote:
> This is on an ASUS Eee PC netbook with 512Mb memory and a 4Gb SSD and a 
> 8Gb SD card for more disk capacity (4Gb is simply not enough to even 
> install FC10).
> 
> Only /home was on an ext3 partition.  /boot, /, and /var were all ext2 
> partitions.
> 
> And things had been running well for a month or so. Regularly on cold 
> boot, it would do an auto check on one of the ext2 partitions and 
> reboot.  Looked good....
> 
> Last night I suspended the box while plugged into AC; this worked well 
> and it came right out of suspension this morning (on battery I use 
> hibernate to save the battery).  I then did a yum update.
> 
> The yum update was taking some time and the screensaver kicked in. For 
> some reason this triggered the box to go into suspension (it never went 
> into hibernation when I hibernated then yum update).  I 'knew' bad 
> things were going to happen to suspend right in the middle of a yum 
> update...
> 
You might look at your screensaver settings WRT power saving, you may have shot 
yourself in that foot. Using ext3 is hard on battery life. Also note there have 
been recent discussions of ext4 behavior if you shut down hard after writing and 
before the timer has physically written your data. I don't have details here, so 
I don't want to spread FUD, but a kernel patch was discussed, and the behavior 
as described does sound somewhat dangerous for laptop operation.

Okay, the URL was in my history, make you own evaluation:
http://www.h-online.com/open/Possible-data-loss-in-Ext4--/news/112821

I'm not going to depend on prayer to save my data until 2.6.30 is out and the 
fix is tested, not do I agree with Ted T'so that the applications should be 
fixed. IMHO any sequence of legal system calls should not zero out the files 
written..., certainly rewriting a block in a file is a pretty normal database 
operation, and should work at least as well as ext3.
> Sure enough, inodes broken all over the place.  Could NOT recover.  
> Fortunately, there was nothing lost other than time.
> 
> I am rebuilding the system right now.  I am keeping the partitions as I 
> had them, but they will all be ext3 and I will change fstab for noatime...
> 
> 


-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot