cvs commit: src/sys/kern kern_shutdown.c

[Nate Lawson]

Peter Jeremy wrote:
> On Wed, 2004-Jul-21 15:57:30 -0600, Scott Long wrote:
>>Implementing a journalling filesystem would be a much more beneficial
>>use of time here.
> 
> You still wind up with unwritten data in RAM, just less of it.
> 
> How much effort would be required to add journalling to UFS or UFS2?
> How big a gain does journalling give you over soft-updates?

Kirk pointed out something to me the other day which many people don't 
think about.  None of the journaling systems has had its recovery mode 
fully tested, especially on very large systems (dozen TB).  It turns out 
that memory pressure from per-allocation unit state is a big problem 
when you are trying to recover a huge volume.

Just because it says "journaling" doesn't make it good.

-- 
-Nate