Trials and tribulations on mirroring....

[Michael C. Shultz]

On Tuesday 18 January 2005 09:46 pm, Karl Denninger wrote:
> Hi folks;
>
> 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 to.
>
> 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. Bummer....
>
> 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 the moment.
>
> 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 option either.
>
> 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...

I had a pentium 166 with four matched ide drives set up as Striped 
plexes that had better disk access than my current 1ghz system. I sure 
miss that!  The only time FreeBSD let me down when they let stopped 
supporting vinum.  Guess no OS is perfect <sigh>

-Mike