Dynamic to basic disk?


D

DWalker

Assuming there are no mirror sets, extended partitions, and no more than 4
partitions on a disk, WHY IN THE WORLD doesn't Microsoft provide code that
lets us convert a dynamic disk volume to a basic volume without losing
data?

I have a mirrored disk (boot disk) on our server that I would like to make
larger. I should be able to break the mirror, convert the volume to basic,
delete the partition following the boot partition (which is a backup boot
partition), use DISKPART to extend the volume, then convert back to a
dynamic again and recreate the mirror.

(I am aware that I can extend a volume on a dynamic disk, into any
unallocated space, but I want to make sure it becomes one contiguous
partition.)

There are other reasons that we might want to convert dynamic to basic --
for example, using Partition Magic or its cousins... most of which only
work on basic disks. Having to lose all of the data just seems like the
programmers didn't want to be bothered with writing this code. Surely it's
not rocket science! I could look into writing a utility myself, except I
understand that the format of the dynamic disk database is not documented.

Ugh.


David Walker
 
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S

Shenan Stanley

DWalker said:
Assuming there are no mirror sets, extended partitions, and no more
than 4 partitions on a disk, WHY IN THE WORLD doesn't Microsoft
provide code that lets us convert a dynamic disk volume to a basic
volume without losing data?

I have a mirrored disk (boot disk) on our server that I would like
to make larger. I should be able to break the mirror, convert the
volume to basic, delete the partition following the boot partition
(which is a backup boot partition), use DISKPART to extend the
volume, then convert back to a dynamic again and recreate the
mirror.

(I am aware that I can extend a volume on a dynamic disk, into any
unallocated space, but I want to make sure it becomes one contiguous
partition.)

There are other reasons that we might want to convert dynamic to
basic -- for example, using Partition Magic or its cousins... most
of which only work on basic disks. Having to lose all of the data
just seems like the programmers didn't want to be bothered with
writing this code. Surely it's not rocket science! I could look
into writing a utility myself, except I understand that the format
of the dynamic disk database is not documented.

http://mypkb.wordpress.com/2007/03/28/how-to-non-destructively-convert-dynamic-disks-to-basic-disks/
 
D

DWalker

convert-
dynamic-disks-to-basic-disks/

Yes, there are some third-party utilities available here and there, some
of which which are quite expensive, and there are some sites (including
a Microsoft KB article) that talk about zapping bytes in the disk
partition table.

That doesn't answer my original question, though.


David
 
S

Shenan Stanley

DWalker said:
Assuming there are no mirror sets, extended partitions, and no more
than 4 partitions on a disk, WHY IN THE WORLD doesn't Microsoft
provide code that lets us convert a dynamic disk volume to a basic
volume without losing data?

I have a mirrored disk (boot disk) on our server that I would like
to make larger. I should be able to break the mirror, convert the
volume to basic, delete the partition following the boot partition
(which is a backup boot partition), use DISKPART to extend the
volume, then convert back to a dynamic again and recreate the
mirror.

(I am aware that I can extend a volume on a dynamic disk, into any
unallocated space, but I want to make sure it becomes one contiguous
partition.)

There are other reasons that we might want to convert dynamic to
basic -- for example, using Partition Magic or its cousins... most
of which only work on basic disks. Having to lose all of the data
just seems like the programmers didn't want to be bothered with
writing this code. Surely it's not rocket science! I could look
into writing a utility myself, except I understand that the format
of the dynamic disk database is not documented.

Shenan said:
Yes, there are some third-party utilities available here and there,
some of which which are quite expensive, and there are some sites
(including a Microsoft KB article) that talk about zapping bytes in
the disk partition table.

That doesn't answer my original question, though.

Your original question is unlikely to get an answer in a peer-to-peer
newsgroup without psychics. ;-)

After all - how would anyone know conclusively why Microsoft does/doesn't do
something - particularly as esoteric as dealing with Dynamic Disks? If you
have to move your data around enough to make a utility like what you ask
about necessary - I think perhaps there was some bad planning going on
and/or it's time to upgrade something. ;-)
 
D

DWalker

convert-
dynamic-disks-to-basic-disks/

.... Postscript: The MS KB article that is referenced in the link that
you sent says:

"This process works only if you have not used any one of the new
features of dynamic disks. These features include extending a partition
or using software redundant array of independent disks (RAID)."

But I have used software RAID, so that option might be out. Even if I
break the mirrors, it's not clear if the process will work. (The
wording says it won't work if you HAVE USED (past tense) the new
features of dynamic disks. So from the plain language, it won't work.)

The "testdisk" method first says to copy all of the files to a separate
partition. Is this just for backup? At the end, it says "This is where
you can make the dynamic to basic drive conversion happen." Just
writing the "new" partition information to the disk makes it into a
basic disk? It's not entirely clear. Why would I write a "new"
partition structure to disk? I want the existing partition structure
that's reflected in the dynamic disk database, written to the old-style
partition table. Maybe that's what "testdisk" does. It's third-party,
unsupported software, so it's a little scary.

David Walker
 
S

Shenan Stanley

DWalker said:
... Postscript: The MS KB article that is referenced in the link
that you sent says:

"This process works only if you have not used any one of the new
features of dynamic disks. These features include extending a
partition or using software redundant array of independent disks
(RAID)."

But I have used software RAID, so that option might be out. Even
if I break the mirrors, it's not clear if the process will work.
(The wording says it won't work if you HAVE USED (past tense) the
new features of dynamic disks. So from the plain language, it
won't work.)

Software RAID) is a horrible performance idea and I wouldn't trust my data
with one either. I equate it with the driver overlay applications - if
something goes wrong - it will go horribly wrong.

Hardware RAIDs are worth their weight in the small extra cost they will
cause initially. It's a lot easier to recover and better over all.

Not to mention that the only time a MIRROR RAID does anygood is during a
hardware failure - and to be honest - that does not happen as often as a
software (human even) error - which would, in a mirror RAID - just replicate
to the other drive instantly - causing the problem to erase in both
situations.
The "testdisk" method first says to copy all of the files to a
separate partition. Is this just for backup? At the end, it says
"This is where you can make the dynamic to basic drive conversion
happen." Just writing the "new" partition information to the disk
makes it into a basic disk? It's not entirely clear. Why would I
write a "new" partition structure to disk? I want the existing
partition structure that's reflected in the dynamic disk database,
written to the old-style partition table. Maybe that's what
"testdisk" does. It's third-party, unsupported software, so it's a
little scary.

It is just for backup - a little scary to me would be using any software
RAID. I would never recommend a software RAID unless there was just no
alternative (and as there is - inexpensive hardware RAID...)

This is all purely side-bar stuff, but...

What is it you are hoping to do with a software-based mirror RAID?

If it is data protection from yourself/the more-likely software issues
(virus, trojans, worms, malware, slip of the human fingers, etc) --> unless
you have a time delay on the mirroring, that's going to fail miserably. If
it is from hardware failure - it may very well have you going in short
order - but in my experience, if it is software based, it's almost as long
as it would have been if you had instead fllowed good backup rituals and
restored from those. *grin* Hardware based mirroring - you'll be back up
pretty quickly - but I still recommend a good backup scheme as opposed to
the mirroring. Software RAID of ANY kind just does not compare with
hardware RAID in performance, ease of use or reliability.

I realize it may seem like a bad investment - but a simple RAID card will do
things for you well worth the money. Also, backups are better protection
against the most common failures than a MIRROR RAID will be. The only
situation that MIRROR RAIDs win is a hardware failure on the first disk(s) -
then you can bring up the other set relatively painlessly. In my
experience - during that time, something software-wise will be lost in the
meantime. Those MTBFs are just huge with hard disk drives. ;-)
 
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G

Guest

Shenan Stanley said:
Not to mention that the only time a MIRROR RAID does anygood is during a
hardware failure

True, and sometimes not even then. I had a situation where a Netware server
suffered a disk controller-card failure in a mirrored pair, and the 'death
thrash' of its SCSI controller corrupted the other disk too. The only
advantage of the mirror was that I was able to get the backup software to run
from the partially-corrupted disk, which avoided having to start from bare
metal. But, I still had to use a tape backup.

One of the strongest arguments against RAID of any kind is that in most
cases it precludes the use of disk-imaging utilities. This makes it much more
difficult to have any kind of rapid-recovery plan in place. If the array does
break then you're facing the full downtime of a bare-metal rebuild, possibly
several hours, maybe a day or two. Whether this is acceptable obviously
depends on the role of the machine, and how much the downtime will cost in
terms of idle staff.
 
S

Shenan Stanley

Shenan said:
Not to mention that the only time a MIRROR RAID does anygood is
during a hardware failure
True, and sometimes not even then. I had a situation where a
Netware server suffered a disk controller-card failure in a
mirrored pair, and the 'death thrash' of its SCSI controller
corrupted the other disk too. The only advantage of the mirror was
that I was able to get the backup software to run from the
partially-corrupted disk, which avoided having to start from bare
metal. But, I still had to use a tape backup.

One of the strongest arguments against RAID of any kind is that in
most cases it precludes the use of disk-imaging utilities. This
makes it much more difficult to have any kind of rapid-recovery
plan in place. If the array does break then you're facing the full
downtime of a bare-metal rebuild, possibly several hours, maybe a
day or two. Whether this is acceptable obviously depends on the
role of the machine, and how much the downtime will cost in terms
of idle staff.

I have used Symantec Ghost (8.2) a few times this past week on a striped
hardware RAID and once on a hardware RAID5. I have had no issues using
imaging products to make/apply images from/to hardware RAIDed systems.
After all - if the hardware is doing the work - the imaging application
doesn't know any different. I have also used Veritas (Symantec now) to do
similar restores (bare metal included with their product add-on) to such
systems. Some server systesm, some higher-end workstations.

I am not pushing Symantec here - it is just my most recent experience with a
RAID (hardware) setup and imaging products. Since I can boot some of the
same systems with BartPE (with proper drivers injected) and see the data
from there on the hardware RAID - I'm sure many other things are possible
with the hardware RAID...
 
A

Al Dykes

Your original question is unlikely to get an answer in a peer-to-peer
newsgroup without psychics. ;-)

After all - how would anyone know conclusively why Microsoft does/doesn't do
something - particularly as esoteric as dealing with Dynamic Disks? If you
have to move your data around enough to make a utility like what you ask
about necessary - I think perhaps there was some bad planning going on
and/or it's time to upgrade something. ;-)


I got burned by dynamic disks-as-default. I had never worked on
dynamic disks before and have only formatted disks and made NTFS file
systems about a zillion times from the first day NTFS shipped. It was
a w2k desktop and I added a big SATA disk as backup of a C drive (two
SATA disks, actually, becuse I know sh*t happens.) I always did a
readback verify of a backup. They always worked. It was Acronix TI
and I did this under w2k.

When my C drive crashed, I booted Acronis from the CD and found out
the hard way that all my backups were in vain, at least for a
30-minute cookbook recovery.

I built a second system and mounted those disks.

Acronis could have given me a warning when I did a backup to a dynamic
file system.

I'm grateful that it didn't happen to one of my clients.
 
D

DWalker

Software RAID) is a horrible performance idea and I wouldn't trust my
data with one either. I equate it with the driver overlay
applications - if something goes wrong - it will go horribly wrong.
It is just for backup - a little scary to me would be using any
software RAID. I would never recommend a software RAID unless there
was just no alternative (and as there is - inexpensive hardware
RAID...)

This is all purely side-bar stuff, but...

What is it you are hoping to do with a software-based mirror RAID?

If it is data protection from yourself/the more-likely software issues
(virus, trojans, worms, malware, slip of the human fingers, etc) -->
unless you have a time delay on the mirroring, that's going to fail
miserably. If it is from hardware failure - it may very well have you
going in short order - but in my experience, if it is software based,
it's almost as long as it would have been if you had instead fllowed
good backup rituals and restored from those. *grin* Hardware based
mirroring - you'll be back up pretty quickly - but I still recommend a
good backup scheme as opposed to the mirroring. Software RAID of ANY
kind just does not compare with hardware RAID in performance, ease of
use or reliability.

I realize it may seem like a bad investment - but a simple RAID card
will do things for you well worth the money. Also, backups are better
protection against the most common failures than a MIRROR RAID will
be. The only situation that MIRROR RAIDs win is a hardware failure on
the first disk(s) - then you can bring up the other set relatively
painlessly. In my experience - during that time, something
software-wise will be lost in the meantime. Those MTBFs are just huge
with hard disk drives. ;-)

Well, it was set up that way for disk crashes. We have had some disk
crashes, and the software RAID saved us. (We also have online nightly
backups to other disks, and offline nightly backups to tape.)

The server is only used to store some user files, and we have not
NOTICED any performance problems at all using Windows 2000 server's
built-in software mirroring. (Although "regenerating a mirror set" does
take a while on a 200 GB partition.)

Using the NOW-inexpensive hardware RAID is certainly a good idea, but
hardware RAID was expensive when we put this server together 5-7 years
ago.

The boot disk was generously sized at 4 GB years ago when Windows 2000
first came out, back when the mentality was that anything over cylinder
1024 or whatever might not be bootable, with fresh memories of the
Windows NT 4 days when there were other limits that you might or might
not see depending on your setup. Even though those limits didn't apply
to us any more, I thought 4GB would be huge for a boot partition. (And
it was, at the time.) Nowadays, I often make 20 GB boot partitions.

(I'm not a fan of chopping up a large disk into many smaller partitions;
I figure that organizing data in folders is fine, and you don't have to
guess which "partition" will need to grow more than any other in the
future.)

Now that 500 GB SATA disks are $110, we don't worry so much about how to
partition things.

But thanks for the comments; I agree about inexpensive hardware RAID
that is now available.

David Walker
 
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D

DWalker

Your original question is unlikely to get an answer in a peer-to-peer
newsgroup without psychics. ;-)

After all - how would anyone know conclusively why Microsoft
does/doesn't do something - particularly as esoteric as dealing with
Dynamic Disks? If you have to move your data around enough to make a
utility like what you ask about necessary - I think perhaps there was
some bad planning going on and/or it's time to upgrade something. ;-)

Yes, I know this is a peer newsgroup, but I know that MS reads it
sometimes. As I said in a reply to a later post in this thread, we made 4
GB boot partitions that seemed generous 5 years ago but seem a little small
now. In hindsight, it was poor planning. At the time, it seemed like
great planning.

I don't move data around much, but once every 5 years some reorganizing
helps...

David
 
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