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Last week (Sep 10) I worked a whole day (on my Ubuntu 12.04 HP elitebook 8530p laptop) using a tex editor (TexWorks) and Jabref to maintain a Bibtex library. Today however I noticed all my modifications of that day are lost! The 'Date Modified' date on the files indicate the last changes two weeks ago (Sep 4). My first reaction was to look at the editors for not properly saving due to either program bugs or file permission problems but after finding no problems and when I launched my online backup program CrashPlan (which saves file modifications every 15 minutes) my latest modified files had been stored properly online!

I believe this means the files were available and saved properly on the file system, backup-ed, but however somehow the changes were lost afterwards. My worry is that my new Seagate hybrid drive (ST95005620AS Momentus XT) is either causing this by itself or in 'cooperation' with the hibernate/suspend or other Ubuntu functionality.

I installed the Seagate now 2 months ago and to get Ubuntu on my disk I copied (I believe using ddrescue or dd) my old HD content (that I replaced because of a few bad sectors) directly on this Hybrid drive. The drive has thus far shown no errors, and (as I program in Java quite a bit on big projects with 100s of modified files on this machine) no similar problems have occurred with different files.

The tex and bib files did have long filenames (including '&' sign). For now I have copied my work to new files but this does have me worried!

Some system info:

fdisk -l:
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0006f049

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      782335      390144   83  Linux
/dev/sda2          782336    20314111     9765888   82  Linux swap / Solaris
/dev/sda3        20316158   976773119   478228481    5  Extended
/dev/sda5        20316160    59375615    19529728   83  Linux
/dev/sda6        59377664    98437119    19529728   83  Linux
/dev/sda7        98439168   976773119   439166976   83  Linux

One message in my syslog that could be related:

[  251.033263] EXT4-fs (sda7): Unaligned AIO/DIO on inode 7474846 by VirtualBox; performance will be poor.

Searching for solutions for this however pointed me towards misalignment of the file systems in the vdi files itself (unless I misunderstood?).

Besides the tex files I believe I also changed icons on my launcher that later (next day) were set back, so possibly more modifications have been lost.

My hunch is that the SSD caching mechanism somehow loses its latest changes and reverts back to a version on the regular platter? Could the disk copy from my non-Hybrid drive to Hybrid drive have caused any issues?

Any thoughts are welcome, Thanks!

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You don't happen to be dual booting with a release preview of Windows 8? This is known to cause some problems. –  fluteflute Sep 15 '12 at 13:49
    
I'm not dual-booting, only ubuntu. I (sadly) only run Windows 7 in a Virtualbox VM to keep connected to Exchange. –  user89769 Sep 15 '12 at 15:52
    
Shouldn't a misaligned partition merely hurt performance? It shouldn't be corrupting your filesystem. –  Mechanical snail Dec 19 '12 at 0:47
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