Installing a system to use both gjournal and gmirror

perryh at perryh at
Sun Aug 1 05:00:52 UTC 2010

Adam Vande More <amvandemore at> wrote:

> > * Since I can't mirror or journal a FAT32 slice AFAIK,
> You can do both to it, it just won't be able to handle the journal.
> Mirroring is just fine.  GEOM stuff works at the block level making
> it filesystem independant.

Wouldn't journalling a FS that doesn't support it be wasted effort?

I suppose mirroring would work as long as the partition were written
only by FreeBSD.  Anything written by DOS or Windows would not get
mirrored, resulting in confusion as to which copy was correct, no?

> >  and there seems little point in mirroring swap or /tmp ...
> While you are correct there isn't much point in mirroring swap
> and tmp, there also isn't much point in trying to save the space
> either.  It's not very much relatively and if you use it for
> something else you impact the performance of your disks.

Granted there may not be a lot of space involved, but I don't follow
you WRT performance impact.  If anything I'd think that independent
equal-sized swap partitions on separate channels should perform
better than if they were mirrored, since any given write would be
performed on only one of them vs on both.


That's the how-to whose 8.1-RELEASE version I had already looked at.
I didn't see any mention of performance, nor of mirroring, nor of
how to intervene after sysinstall has sliced and partitioned the
disks and before it starts installing the distributions -- the last
being necessary if the data and journal are to share a partition.
Did I miss something?

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