gmirror RAID-1: rebuilding freezes machine

[Jo Rhett]

On Thu, Sep 14, 2006 at 07:42:25AM -0400, Michael Butler wrote:
> I've been bitten by this - make sure that the first slice on the
> mirrored partition does not start at offset 0.
> 
> For example, this disk is mirrored on slice 2 ..
> 
> imb at aaron:/home/imb> sudo bsdlabel mirror/gm0s2
> # /dev/mirror/gm0s2:
> 8 partitions:
> #        size   offset    fstype   [fsize bsize bps/cpg]
> ~  a:   524272       16    4.2BSD     2048 16384 32768
> ~                ^^^^^^^
> ~  c: 284655734        0    unused        0     0    # "raw" part ..
> ~  d:  1048576   524288    4.2BSD        0     0     0
> ~  e:  1048576  1572864    4.2BSD        0     0     0
> ~  f: 282034294  2621440    4.2BSD        0     0     0
 

What is the problem with this?  And how would one avoid it?

I've got quite a few production systems with this:

# bsdlabel mirror/gm0s1
# /dev/mirror/gm0s1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  a:  4194304        0    4.2BSD     2048 16384 28552
  b:  4194304  4194304      swap
  c: 586067202        0    unused        0     0         # "raw" part, don't edit
  d: 67108864  8388608    4.2BSD     2048 16384 28552
  e: 188743680 75497472    4.2BSD     2048 16384 28552
  f: 321826050 264241152    4.2BSD     2048 16384 28552

-- 
Jo Rhett
senior geek
SVcolo : Silicon Valley Colocation