Trials and tribulations on mirroring....
karl at denninger.net
Tue Jan 18 21:46:08 PST 2005
I've been running 4.x quite happily for some time, and am trying to set up a
box with 5.3 that hopefully will end up being a viable platform to move over
Tried on both 5.3-RELEASE and 5.3-STABLE (built this evening)
Having some problems here...
First, I discovered that vinum isn't "quite right" with 5.3. Ok, so I moved
to "gvinum", but ran into some really bizarre behavior there too, where it
was detaching subdisks apparently at random and on a rebuild would
occasionally crash with some really wild results. It also doesn't
load-balance reads (barf). All this was discovered after I spent an
afternoon getting it set up properly with the "shadow" root and all.
The instability is a real deal-breaker - this is supposed to (eventually)
be a production server, so it can't be "squirrelly".
So, my next attempt (with a new, fresh load) was to give gmirror a shot
instead, since I only need Raid 1, and this looks like a "better" option
from that perspective given gvinum's squirrely and not-all-there status at
Weeeeellll.. the manual page (and the archives on the list here) implies that
I can do the following:
1. Set up the system on one of the two mirror disks.
2. In single user mode, use "gmirror label -v -b round-robin disk ad4"
to set up the pre-existing disk (with data on it), which I booted from,
as the "primary".
3. Then use "gmirror insert disk ad6" to add the secondary (mirrored) disk,
which will automatically sync it and bring them into a consistent state.
Only one small problem - the first command (in #2) fails, with:
"Can't store metadata on ad4: Operation not permitted"
This is true if the system is mounted read-only (in single user mode) or
read-write (in multiuser, with all filesystems mounted)
Attempting to label the SECOND (bare) disk works, but of course that's
backwards and an "insert" would immediately destroy the running system (I
assume it would also fail with the same permission error, but I've not tried
it) - so that's not an option.
I also tried it from the fixit disk, but the KLD cannot be loaded from the
fixit disk, and none of the commands work - so that appears to not be an
How do you get this thing set up? The archives here (and man pages)
strongly imply that this works for a root filesystem and boot drive -
what am I missing?
Need a Raid 1 solution that works to move over to the 5.x world out here...
Karl Denninger (karl at denninger.net) Internet Consultant & Kids Rights Activist
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