Re: Adding Raidframe to existent GPT system

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Mon, 09 May 2022 10:01:47 -0400
    From:        =?UTF-8?Q?C=C3=A9sar_Catri=C3=A1n_C=2E?= <ccatrian%eml.cc@localhost>
    Message-ID:  <b4108aae-5b20-4a0c-95d5-dc97838be0e2%www.fastmail.com@localhost>

  | Got three drives, two for a RAID-1 array and one more for backup. 

ok, that's good.  At least last time I looked raidframe was unable
to autoconfigure hot spare drives - they need to be added after
each boot, which is a minor inconvenience, as it can easily be scripted
in rc.local ... just watch out for trying to add a drive as a spare
after an earlier faikure has caused the spare to already have been
incorporated into the raid set.

It is also no great problem if you don't set up a hot spare, raidframe
runs fine (without redundancy) if a drive fails (had that happen
several times) then you can add the replacement manually after a
failure.  Just keep an eye on things so you detect faikures quickly,
it is easy to get complacent after years of nothing happening.
Which reminds me...

  | Got it enabled for MBR, but it seems the GPT adds complexity
  | for Raidframe due that each GPT partition is offered as a new
  | disk/wedge to the system.

One man's complexity is another's flexibility.   You can partition
the drive, and make separate raid sets from partitions on different
drives (with more drives to play with, I do things like that,
using parts of different drives for different raid sets).

  | Should be created only one wedge at first, using the entire disk,
  | then apply raidframe to it

You can do that, or break the drives into smaller pieces and
make each of those a separate raid.  It all depends upon your
needs.   It appears from your current GPT that you are using
legacy (BIOS) booting, rather than EFI - that's fine, and NetBSD's
boot allows booting from and root on a raid1 (though someone else
will need to provide the recipe if you want to do that, I don't
run things that way) but the firmware will not undertstand
raidframe, so EFI booting needs an EFI partition in the physical
drive's GPT partition table, not in a raid partion in that.

  | (don't know if raidframe is ready for GPT?), 

It is.   Raidframe just gives you a simulated drive.  Other
than BIOS access you can do anything with a raidframe that
you can with any other drive.

  | then do again a GPT layout into the raid0 device to deploy the
  | filesystems?

That works, if you take care of booting (assuming you plan
on booting from this drive/drives).

The one thing to watch for is partition alignment and stripe
sizes, relative to your filesystem block (newfs -b value)
size, to avoid getting lots of read/modify/write cycles
happening when all that should have happened is to write
a block (once to each drive with RAID 1).   There are other
people better able to explain the issues here than me.

Much better to wait a day or so, get the correct info,
and set things up properly, thandk everything, init tge
raid, set up filesystems, and tgen discover tgat tge config
forces poor performance, and you neex to start over (if
write performance matters, it doesn't always).

kre