Need to make a single 3TB partition

[Yousuf Khan]

Bought a dual-disk USB enclosure and a couple of 1.5TB drives to put
into it. First of all, the enclosure has a built in concatenation
feature. When using that, Windows and Linux both see it as an 800 GB
drive, rather than a 3000 GB drive! So I put it back to regular mode,
and we see two separate 1.5 TB drives again.

Next I tried concatenating through Windows Disk Management. BTW, this is
Windows 7 Ultimate Edition x64. When I use the Spanned Volume wizard, it
gives the error message, "Operation is not supported by object". I then
tried converting each disk from MBR partitions to the new GPT
partitions, it accepted that. I then retried the Spanned Volume wizard,
and the same message appeared. Then I tried converting them to Dynamic
disks, but it showed the "Operation is not supported by object" message
again. I think whatever the problem is, it's from this stage where it
tries to convert to dynamic disks. So why isn't it accepting the
conversion to dynamic disks?

Yousuf Khan

 

[JW]

Bought a dual-disk USB enclosure and a couple of 1.5TB drives to put
into it. First of all, the enclosure has a built in concatenation
feature. When using that, Windows and Linux both see it as an 800 GB
drive, rather than a 3000 GB drive! So I put it back to regular mode,
and we see two separate 1.5 TB drives again.

Next I tried concatenating through Windows Disk Management. BTW, this is
Windows 7 Ultimate Edition x64. When I use the Spanned Volume wizard, it
gives the error message, "Operation is not supported by object". I then
tried converting each disk from MBR partitions to the new GPT
partitions, it accepted that. I then retried the Spanned Volume wizard,
and the same message appeared. Then I tried converting them to Dynamic
disks, but it showed the "Operation is not supported by object" message
again. I think whatever the problem is, it's from this stage where it
tries to convert to dynamic disks. So why isn't it accepting the
conversion to dynamic disks?

Just guessing here, but do USB devices support spanning natively?
See
http://social.answers.microsoft.com.../thread/534f4fa0-7a61-4a23-952f-e034e1137e03/

 

[Arno]

Bought a dual-disk USB enclosure and a couple of 1.5TB drives to put
into it. First of all, the enclosure has a built in concatenation
feature. When using that, Windows and Linux both see it as an 800 GB
drive, rather than a 3000 GB drive! So I put it back to regular mode,
and we see two separate 1.5 TB drives again.

Next I tried concatenating through Windows Disk Management. BTW, this is
Windows 7 Ultimate Edition x64. When I use the Spanned Volume wizard, it
gives the error message, "Operation is not supported by object". I then
tried converting each disk from MBR partitions to the new GPT
partitions, it accepted that. I then retried the Spanned Volume wizard,
and the same message appeared. Then I tried converting them to Dynamic
disks, but it showed the "Operation is not supported by object" message
again. I think whatever the problem is, it's from this stage where it
tries to convert to dynamic disks. So why isn't it accepting the
conversion to dynamic disks?

Yousuf Khan

Maybe Windows thinks that you cannot possibly want to span on
removable devices? It has this habit of thinking it knows
what you do and do not want but at the same time is far too
stupid to pull it off.

Incidentially the 800GB seems to be a problem with the enclosure,
there is no limit (that I know of) at 39.5 bit adress length.
Maybe give this pice of trash back?

USB storage supports both SCSI 32 and SCSI 64 bit sector numbers.

Arno

 

[Yousuf Khan]

Just guessing here, but do USB devices support spanning natively?
See
http://social.answers.microsoft.com.../thread/534f4fa0-7a61-4a23-952f-e034e1137e03/

Well according to that, it looks like (at least as of Windows 2000)
dynamic disks weren't supported on USB or Firewire disks.

Yousuf Khan

 

[Yousuf Khan]

A much more fundamental question is whether you really want to do that.

Yeah, I do, I don't care about the points of failure argument. This is
going to be used as a backup device, for my other drives. It's going to
be unplugged and/or unpowered most of the rest of the time.

Yousuf Khan

 

[Yousuf Khan]

Maybe Windows thinks that you cannot possibly want to span on
removable devices? It has this habit of thinking it knows
what you do and do not want but at the same time is far too
stupid to pull it off.

Yeah, it looks like the case here. The technote says Microsoft doesn't
support this on USB or Firewire drives.

Incidentially the 800GB seems to be a problem with the enclosure,
there is no limit (that I know of) at 39.5 bit adress length.
Maybe give this pice of trash back?

Is it possible that there is a BIOS limitation, beyond 2TB? The
motherboard I'm using is a rather plain desktop mobo, it may not be
expecting such huge devices to join in?

USB storage supports both SCSI 32 and SCSI 64 bit sector numbers.

Does the Windows USB mass storage driver treat them as SCSI devices?

Oh, BTW, when I tried spanning them through Windows' spanning wizard
(during initial setup prior to receiving the error message), it accepted
the combined size as 2794 GB, however it would only allow a filesystem
size of half of that to be created, 1397 GB! That's also the exact size
of each individual drive. So it looks like it wasn't going to accept
being spanned over two disks no matter what.

I also tried using Linux's LVM to do this, and it created similarly
sloppy results. I don't think it's got anything to do with any
limitations that the enclosure has, as the problems seem to be universal
throughout Windows and Linux.

Yousuf Khan

 

[Rod Speed]

Yousuf Khan wrote

JW wrote

Well according to that, it looks like (at least as of Windows 2000)
dynamic disks weren't supported on USB or Firewire disks.

It wouldnt be surprising if it isnt supported in any version of win,
essentially because thats very risky with removable drives.

 

[Rod Speed]

Yeah, it looks like the case here. The technote says Microsoft doesn't
support this on USB or Firewire drives.


Is it possible that there is a BIOS limitation, beyond 2TB? The
motherboard I'm using is a rather plain desktop mobo, it may not be
expecting such huge devices to join in?


Does the Windows USB mass storage driver treat them as SCSI devices?

Oh, BTW, when I tried spanning them through Windows' spanning wizard
(during initial setup prior to receiving the error message), it
accepted the combined size as 2794 GB, however it would only allow a
filesystem size of half of that to be created, 1397 GB! That's also
the exact size of each individual drive. So it looks like it wasn't
going to accept being spanned over two disks no matter what.

I also tried using Linux's LVM to do this, and it created similarly
sloppy results. I don't think it's got anything to do with any
limitations that the enclosure has, as the problems seem to be
universal throughout Windows and Linux.

Likely because they all decide that its much too risky to allow with removable drives.

Corse in your case both drives are in the same box, but its clear why they are being
so conservative when the result when one of the drives is removed is so catestrophic.

 

[Yousuf Khan]

Yousuf Khan wrote


It wouldnt be surprising if it isnt supported in any version of win,
essentially because thats very risky with removable drives.

Now the question is what would let me span these two drives together?

Yousuf Khan

 

[Arno]

Yeah, it looks like the case here. The technote says Microsoft doesn't
support this on USB or Firewire drives.

Well, it does make some sense. Personally, I think the idea
of "removable" devices is fundamentally flawed, and mounting and
umounting as in Linux/unix is the far better approach. Bit apparently
MS customers just yank out devices if it is mechanically possible.
That could be a deisaster if the devices are RAIDed/

Is it possible that there is a BIOS limitation, beyond 2TB? The
motherboard I'm using is a rather plain desktop mobo, it may not be
expecting such huge devices to join in?

USB does not go over the BIOS, at least not in Linux. 2TB is 41
bit. No limit on byte level I can see. Number of sectors would
be 32. Ah, I think I see the problem. USB is using the storage
SCSI command set. It has either 32 bit or 64 bit for the sector
number. If the enclosure is resonably current, it should
support 64 bit sector numbers. Linux need compiled in kernel
support for large block devices to be able to handle block
devices > 2TB. This support has been there for some years, but
may be missing from your kernel. The config option is
CONFIG_LBDAF and found under "enable block layer" in 2.6.32.

I have no idea whether XP supports 64 bit sector numbers, but
apparently not.

Does the Windows USB mass storage driver treat them as SCSI devices?

Yes., but may be missing support for 64 bit sector numbers.

Oh, BTW, when I tried spanning them through Windows' spanning wizard
(during initial setup prior to receiving the error message), it accepted
the combined size as 2794 GB, however it would only allow a filesystem
size of half of that to be created, 1397 GB! That's also the exact size
of each individual drive. So it looks like it wasn't going to accept
being spanned over two disks no matter what.

I also tried using Linux's LVM to do this, and it created similarly
sloppy results. I don't think it's got anything to do with any
limitations that the enclosure has, as the problems seem to be universal
throughout Windows and Linux.

See above. I have had the large block device support enabled
for ages in my own kernels, no negative effect so far.

Arno

 

[Arno]

Now the question is what would let me span these two drives together?

I think it is an OS issue, see my other posting.

Arno

 

[Rod Speed]

Yousuf Khan wrote

Rod Speed wrote

Now the question is what would let me span these two drives together?

The drive itself clearly does that. You need to ask the manufacturer why
it doesnt appear as the full size, presumably its a common problem.

 

[Char Jackson]

Now the question is what would let me span these two drives together?

Yousuf Khan

You might have some luck by using a true RAID controller, perhaps with
eSATA port(s), rather than messing with USB, unless this thing needs
to be semi-portable. If you went with RAID the drive enclosure would
still be used as a physical home and to supply power to the drives,
but the data connection would be to the RAID controller instead of
USB.

 

[Yousuf Khan]

Well, it does make some sense. Personally, I think the idea
of "removable" devices is fundamentally flawed, and mounting and
umounting as in Linux/unix is the far better approach. Bit apparently
MS customers just yank out devices if it is mechanically possible.
That could be a deisaster if the devices are RAIDed/




USB does not go over the BIOS, at least not in Linux. 2TB is 41
bit. No limit on byte level I can see. Number of sectors would
be 32. Ah, I think I see the problem. USB is using the storage
SCSI command set. It has either 32 bit or 64 bit for the sector
number. If the enclosure is resonably current, it should
support 64 bit sector numbers. Linux need compiled in kernel
support for large block devices to be able to handle block
devices > 2TB. This support has been there for some years, but
may be missing from your kernel. The config option is
CONFIG_LBDAF and found under "enable block layer" in 2.6.32.

I asked the same question to Janos Mathe, the developer of HD Sentinel,
he believes that the USB-SATA chipset is to blame here. These are his words:

It seems it is an overflow issue in addressing.
I'm sure it is not related to BIOS as the BIOS would only cause troubles
on disks which are under its control (for example if they were connected
to the motherboard and you'd try to boot from it). USB devices are controlled by the USB drivers of the OSes (Windows/Linux).

I suspect the problem is related to the JMicron USB-ATA bridge which
translates the USB packets to ATA commands sent to the SATA drives.
I quickly checked the specs of this chip at http://www.jmicron.com/PDF/JM20336/JM20336.pdf
but as I see, JMicron do not mention the maximum drive capacity to be used.
However, I think at the time of release (2005) they were not prepared
for such BIG concatenated array and that's why the LBA addressing wraps around over 2 TB.
If I can help, please let me know.

So it looks like there may be nothing that can be done here.

Yousuf Khan

 

[Char Jackson]

I asked the same question to Janos Mathe, the developer of HD Sentinel,
he believes that the USB-SATA chipset is to blame here. These are his words:


So it looks like there may be nothing that can be done here.

Yousuf Khan

Was my suggestion (RAID controller versus USB controller) considered?

 

[JEDIDIAH]

Well, it does make some sense. Personally, I think the idea
of "removable" devices is fundamentally flawed, and mounting and
umounting as in Linux/unix is the far better approach. Bit apparently
MS customers just yank out devices if it is mechanically possible.
That could be a deisaster if the devices are RAIDed/

Any good RAID setup is going to have removable devices. That's kind
of part of the point of the whole thing. So the fact that you can
disconnect a USB drive isn't a terribly distinctive thing here. It really
shouldn't matter.

[deletia]

 

[Yousuf Khan]

Was my suggestion (RAID controller versus USB controller) considered?

The problem with putting the drives through a RAID controller is that
I'd have to bring these drives into the computer case and and connect
them permanently. I am trying to keep them as backup drives, therefore
they need to remain in the external case.

 

[Yousuf Khan]

Any good RAID setup is going to have removable devices. That's kind
of part of the point of the whole thing. So the fact that you can
disconnect a USB drive isn't a terribly distinctive thing here. It really
shouldn't matter.

Well, they don't want the drives to be *that* removable. There's a
difference between being swappable and portable. USB drives would be
considered portable.

Yousuf Khan

 

[Arno]

I asked the same question to Janos Mathe, the developer of HD Sentinel,
he believes that the USB-SATA chipset is to blame here. These are his words:

So it looks like there may be nothing that can be done here.

Yousuf Khan

Hmm. Could be right. Missing large block device support in Linux
should not make it show up as smaller, just prevent it from being
used in its full capacity. Seems indeed that you are out of luck.

Arno

 

[Robert Nichols]

Well, they don't want the drives to be *that* removable. There's a
difference between being swappable and portable. USB drives would be
considered portable.

Indeed! The SATA connector is rated for a life of just 50 insertions.
You will run into that pretty quickly if you're swapping backup drives
around.