Re: Mirror one 72 gig disk on another.

From: Darren Dunham (ddunham_at_redwood.taos.com)
Date: 09/22/04 

Date: Wed, 22 Sep 2004 15:23:38 GMT

ds <not@now.invalid> wrote:
> "Juhan Leemet" <juhan@logicognosis.com> wrote in message
> news:pan.2004.09.22.06.04.47.813007@logicognosis.com...
>> >
>> >> prtvtoc /dev/rdsk/cAtBdCs2 | fmthard -s - /dev/rdsk/cXtYdZs2
>> >
>> >> Now, what *I* would like to know is, for SURE does this ALSO
>> >> make diskb bootable, i.e. copy the boot record?? My
>> >> understanding is that it does.
>> >
>> > No. All 'fmthard' does is to arrange the slices in the VTOC (rather
>> > like 'format' does).

> This is getting interesting (again ;-).
> Since prtvtoc | fmthard arranges the slices in the VTOC, like format
> does, does newfs then need to be applied to all slices of the
> pre-mirror diskb before mirroring? Or, does mirroring *also* create
> the ufs newfs slices?

'newfs' would create a new, blank filesystem. But that's not what you
want. You just want a copy of your existing filesystem.

As the mirror syncs up, all the data in the slice (which includes the
existing filesystem) will be copied. Running 'newfs' to create another
filesystem beforehand is just a waste of time, since it will be
overwritten by the resynchronization.

> Okay, if one forgets to use installboot before mirroring, can it be
> done after mirroring? And yet, isn't the bootblock part of the
> root slice (typcially s0)?

> I have read the Sun doc, and upon reflection, a lot of this is still
> not very clear. (Or, maybe I missed the nuances?)

My assumption was that the resynchronization would copy not only the
filesystem, but also the boot blocks. I don't know that the documents
make explicit which blocks are not synced. That would have implications
for raw database files, but I would assume most of them would also skip
the first 16 blocks, just like a filesystem. 

-- 
Darren Dunham                                           ddunham@taos.com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
         < This line left intentionally blank to confuse you. >

Relevant Pages

  • Re: Mirror one 72 gig disk on another.
    ... does newfs then need to be applied to all slices of the ... You just want a copy of your existing filesystem. ... >> Okay, if one forgets to use installboot before mirroring, can it be ...
    (comp.unix.solaris)
  • newfs and mount vs. half-baked disks
    ... We have a large data area on our disk that ... clean we just newfs and mount the clean new filesystem. ... I emailed Kirk about this state of affairs and he confirmed that newfs ... This would obviously be committed in a separate commit, ...
    (freebsd-arch)
  • Re: [SLE] Cant mount the UnixWare 7.1.4 drive on SUSE Linux 10.0
    ... Or are you attempting this under 10.1RC3 on a different device with VxFS ... filesystem suport in the kernel, there is an additional hurdle that will ... subdivides a fdisk partition into slices, so each slice can be a Unixware ... The beginning of the the partition is not the ...
    (SuSE)
  • Re: Mirror one 72 gig disk on another.
    ... Hi Juhan! ... does newfs then need to be applied to all slices of the ... Why not on a mirror? ...
    (comp.unix.solaris)
  • Re: Passing options to Newfs in the FreeBSD installer
    ... During the FreeBSD installation I would like to pass parameters to the programm ... which creates the filesystem *newfs if I understand that correctly. ... (If you do not have a FreeBSD system available with manpages installed, ...
    (freebsd-questions)