On 15 Jan 2002, at 5:42, Collins Richey boldly uttered: 

> FreeBSD uses the UFS (unix file system) which is not a journaling file
> system.  fsck is required if not cleanly unmounted.  There is a
> feature called Soft Updates that changes the way meta data vs. normal
> data is scheduled to be flushed to the disk.  This is supposed to make
> the file system less error prone, but there are some indications of it
> worsening the problem.  FreeBSD 5.0 is working on changes to the file
> system to allow "fsck-less boot," but I don't know anything more.  The
> lack of a journaling fs is probably the biggest drawback that I can
> see for FreeBSD, with device support being a close second. 
 

For an excellent technical paper on filesystems including comparisons 
between the FreeBSD Softupdates system and some journaling 
filesystems, see the links below.  Excerpt from the abstract:

> Soft Updates holds the promise of providing stronger reliability 
> guarantees than journaling, with faster recovery and superior 
> performance in certain boundary cases.


abstract:
http://www.ece.cmu.edu/~ganger/papers/usenix2000_abs.html

Postscript full paper:
http://www.ece.cmu.edu/~ganger/papers/usenix2000.ps


There is also a new feature of the FreeBSD filesystem that 
dramatically increases performance for certain file writes, I believe 
it is starting to be merged into the base system in 4.5, due out 
later this month.



Phil


--
Philip J. Koenig                                       [EMAIL PROTECTED]
Electric Kahuna Systems -- Computers & Communications for the New Millenium

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