gmirror, geli and gjournal

Terje Elde terje at elde.net
Thu Apr 30 11:26:23 UTC 2009


Hi,

I'm curious about GEOM combining gmirror geli and gjournal.

I'm setting up a rather slow machine (PentiumIII 450Mhz) and didn't want
to encrypt once pr. drive, so I configured geli on top of gmirror so I
encrypt once for the mirror, rather than once for each disk.  Seemed to
make sense.

I now want to place UFS2 filesystems with journaling (using gmirror
offcourse) on top of the encrypted mirror.  In the gjournal man page, I
was pleased to read:

     When gjournal is configured on top of gmirror(8) or graid3(8)
providers,
     it also keeps them in a consistent state, thus automatic
synchronization
     on power failure or system crash may be disabled on those providers.

But what happens if I have geli sitting between gjournal and gmirror?

Will gjournal still take responsibility for keeping the mirror in sync?

Or would I have to have geli and gmirror trade place, so gjournal sits
directly on top of gmirror, and I encrypt once pr. disk?

Also, the way I set things up, I used gmirror and geli on the whole
drives, used BSD disklabels for partitioning the encrypted device, and
understand I'd use gjournal for each partition.  Will things work as
desired even though gmirror is for the whole disk, and gjournal with
UFS2 is pr. partition?

Tried to RTFM, interrogate google, but came up a bit short on these
questions, and since it's about data-integrity, I'd rather ask now, than
cry later.

Hope someone can enlighten me a bit.

Terje



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