[NTLUG:Discuss] Software RAID under 2.6 kernel -- mirroring disks v. partitions (MD only does latter)

[Bryan J. Smith]

Ralph Green, Jr.
> Bryan, Thank you for the detailed response.

A lot of people bash me for detail.  But I'd rather say too much than
not enough.  I try to organize things as best as I can, but sometimes
that's hard to do with a bottom post/quoting response (instead of a top
post).

> About the CF card, I had planned to make it read only.  It is pretty
> rarely that I change the /boot filesystem. 

And that's an excellent strategy.

> The eventual system is going to be a small computer and we barely have
> room for two hard drives.  That is why I was using the CF card at all.
> I am a little concerned about its reliability, even as read only. 

EEPROM is solid state and very reliable as long as you aren't writing to
it a lot.  So I wouldn't be concerned there.  In fact, I thought you
were pretty ingenious in coming up with using a CompactFlash for the
/boot.

> For now, it is an interesting experiment and I'll hopefully let it run
> for a while and see how it does.

Again, using a CF card was pretty ingenious.  I never thought of doing
so.

> I had not considered any of the other issues you raised,

And you won't see many sites either.  The sooner the legacy DOS disk
label of primary/extended partitioning dies, the better IMHO.  Today's
disk labels should store the disk geometry, volume group associations,
etc...

NT 5.x+ LDM (dynamic disks) does, Linux's LVM/LVM2 does, etc... 

-- Bryan

P.S.  I only hope there is more work on the user-space, GRUB support
and distro installer support for LDM.  But at this time, there seems to
be little beyond the kernel support.  The lack of interest is because
people think LDM is a NTFS thing (it's not, although it solves some
issues with NTFS that Microsoft created, but never thought out), when
it's just a better way to partition.  Not the best, but better, and
since Microsoft is pushing it -- and it does allow any OS to know what
disk geometry/translation NT 5.x+ is using, Linux distros might as well
support it for dual-boot configurations.


-- 
     Linux Enthusiasts call me anti-Linux.
   Windows Enthusisats call me anti-Microsoft.
 They both must be correct because I have over a
decade of experience with both in mission critical
environments, resulting in a bigotry dedicated to
 mitigating risk and focusing on technologies ...
           not products or vendors
--------------------------------------------------
Bryan J. Smith, E.I.            b.j.smith at ieee.org