[sf-lug] filesystem for a 3TB external USB drive

[Rick Moen]

Quoting jim (jim at systemateka.com):

> * In your reply you have a number of references to problems 
>   with corrupted data due to power failure. 
>       It seems to me that there are two hardware failure 
>   points that threaten data: disk drive failure and power 
>   supply failure. 

Well, also:

  [...]
  What probably hit you here is caused by the very simple fact that
  PC-class hardware is crap.

  You see, when you yank the power cord out of the wall, not all parts of
  the computer stop functioning at the same time. As the voltage starts
  dropping on the +5 and +12 volt rails, certain parts of the system may
  last longer than other parts. For example, the DMA controller, hard
  drive controller, and hard drive unit may continue functioning for
  several hundred of milliseconds, long after the DIMMs, which are very
  voltage sensitive, have gone crazy, and are returning total random
  garbage. If this happens while the filesystem is writing critical
  sections of the filesystem metadata, well, you get to visit the fun Web
  pages at http://You.Lose.Hard/ .

  I was actually told about this by an XFS engineer, who discovered this
  about the hardware. Their solution was to add a power-fail interrupt and
  bigger capacitors in the power supplies in SGI hardware; and, in Irix,
  when the power-fail interrupt triggers, the first thing the OS does is
  to run around frantically aborting I/O transfers to the disk.
  Unfortunately, PC-class hardware doesn't have power-fail interrupts.
  Remember, PC-class hardware is cr*p.
  [...]

Much more at http://linuxmafia.com/faq/Filesystems/reiserfs.html


On the other bit, Jim, when I saw how vaguely you defined your question,
I decided to kick back and let other people chew up their time on it.
Attempting to pick a suitable filesystem without knowing the requrements
is dumb.

FWIW, if I needed a high degree of data protection and short fsck times
on a multiterabyte filesystem, I wouldn't go fo zfs-fuse, which is not
only inherently slow but also is an ugly hack that will never be
maintainable on account of licence conflict that makes unlawful even any
distribution of binaries, not to mention merger into mainline.

So, in that usage case, what I would use instead is Nexenta, which is
close enough to Debian userspace on a Solaris kernel that I estimate I'd
feel mostly at home.