RFC: Article on implementing UFS journaling on desktop PCs

[Manolis Kiagias]

Joshua Isom wrote:
>
> On Apr 24, 2008, at 12:00 PM, Manolis Kiagias wrote:
>
>> I have just completed an article (mostly how-to) for implementing UFS 
>> journaling on a typical desktop PC:
>>
>> http://store.itsyourftp.com/~sonic2000gr/freebsd/gjournal-desktop/article.html 
>>
>>
>> It focuses on detailing an easy to follow, repeatable procedure, to 
>> install FreeBSD on a typical PC and enable journaling on /usr and 
>> possibly /var.
>> I am using this same procedure on my systems.
>>
>> I welcome all feedback, please send me any comments, suggestions and 
>> corrections.
>>
>> Thanks,
>> Manolis
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>
> "A kernel panic will occur if the journal space is exhausted before it 
> has a chance to be committed."
>
> So the intended behavior is for the kernel to give up(instead of keep 
> trying and maintain reliability), and risk data loss?  With a 
> compliant hard drive that doesn't reorder writes, how is journaling 
> better than soft updates?
>
I was referring mainly to this post:

http://lists.freebsd.org/pipermail/freebsd-questions/2008-April/173501.html

Obviously I am no expert on the subject, but it seems to me that since 
the journal should keep the filesystem consistent, if it fills up and 
can't commit all the bits to disk, it would be better not to commit 
anything. Sure, you may lose data but not the filesystem.

Having said that, the article only deals with the use of journaling on a 
typical desktop. I am already using default 1Gb journals on all my 
desktop systems (at least one works for a few hours under quite heavy 
load) and a home server for an individual who constantly copies several 
very large files over gigabit net (gjournal+gmirror in his case). I have 
never encountered any problem. YMMV, proceed with care.