gjournal and TRIM: A safe combination?

[Julien Cigar]

On Wed, Oct 21, 2015 at 02:38:16PM -0500, Brandon J. Wandersee wrote:
> 
> Julien Cigar writes:
> > Correct me if I'm wrong but, unless there is a bug in Soft Updates (SU),
> > your FS will, in theory, never be corrupted with SU only.
> 
> If I read this right, then, would gjournal be overkill for typical
> desktop/laptop use?  UFS2 is perhaps the only filesystems I've ever
> encountered in common use that doesn't have data journaling enabled by
> default, so that's thrown me off somewhat...

It depends of your needs, but for a typicaly desktop use it seems a bit
overkill to me.

Contrary to other filesystems UFS doesn't need journaling to avoid 
_corruption_ as SU is an alternate approach to maintain metadata
integrity.

One important thing to remember is that neither SU, or SU+J, or any
journaled metadata prevents data loss: corruption != data loss. This is
where gjournal (and data=journal on EXT-like FS) comes in as datas and
metadatas are written in the journal _before_, so you avoid corruption
and data loss.

I hope SU+J will be fixed one day ...

> 
> -- 
> =================================================================
>    		      :: Brandon Wandersee ::
>                   :: brandon.wandersee at gmail.com ::
> ==================================================================
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> completely foolproof is to underestimate the ingenuity of complete
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-- 
Julien Cigar
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