[ale] Very Unusual Delete Problem #2

[Dow Hurst]

Reiserfs or XFS is fine to use as a replacement for ext3 if you want.  
However, the encryption is an added layer between you and the 
filesystem.  Just like the others have said, this puts a very difficult 
to recover from layer between you and your data.  Laptops at risk of 
being stolen are the usual targets of an encrypted filesystem.  Now for 
practical advice:

1.  Go ahead and backup the drive like Geof said so there is a copy of 
the disk.  Hope you've got a disk you can mirror it too!

2.  Check and see if you can boot up and copy the files to another 
machine from your machine so you won't have to deal with encryption on 
that backup.

XFS journals metadata but not data.  So the state of the filesystem will 
be at the "metadata" point when you interrupted the power.  No writes 
are done until the metadata is journaled.  So some small amount of data 
that had not been erased but the "action of it's erasal" had been logged 
would be erased as the log is replayed and the filesystem brought into a 
stable state.

 From now on you can use the encrypted journaled filesystem if you want 
but just rsync it to another backup disk that isn't encrypted but just 
journaled.  Seems that from your email that the filesystem isn't stable 
and some inodes have incorrect data in them pointing to directories that 
no longer exist.  I wonder how that encryption is implemented?  And how 
does the filesystem ride on top of the encryption?  There must be 
something like:

encrypted data <-> encryption kernel module <-> filesystem kernel module 
<-> userspace

Any filesystem read or write would have to go thru two kernel level 
modules to get to the hard drive.  Is this correct?

There is a xfsrepair tool that you can try out.  Under IRIX you run it a 
couple of times and that is all you can do.  I'll look at the docs on 
XFS for linux and see what they say.  Good luck since I know this kind 
of stuff is quite frustrating!  I haven't learned enough about the XFS 
filesystem for Linux yet so must hit the docs to see what might be the 
problem.
Dow


ChangingLINKS.com wrote:

>Because of my growing dislike for RedHat/ext3, I moved on to Suse/XFS(I think 
>XFS) for my server. I used the Suse installation to automatically setup a 
>loop back encrypted filesystem that requires a password to mount (at boot). 
>
>This is where I keep my data. 
>
>Unfortunately, while trying to fix unusual delete problem #1, I apparently 
>deleted files within that encrypted filesystem. I immediately disconnected 
>the electricity. The last backup does not have everything.
>
>Since the filesystem is loaded in RAM(?) was pulling the power the wrong?
>Since the filesystem is loaded in RAM was pulling the power right?
>Is the data removal "saved(written)" already?
>Can data be recovered from an "on the fly" encrypted filesystem?
>  
>

-- 
__________________________________________________________
Dow Hurst                  Office: 770-499-3428
Systems Support Specialist    Fax: 770-423-6744
1000 Chastain Rd. Bldg. 12
Chemistry Department SC428  Email:   dhurst at kennesaw.edu
Kennesaw State University         Dow.Hurst at mindspring.com
Kennesaw, GA 30144
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