Initialising hard drives - I'm confused!

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Ozei

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I've just added a pair of new hard drives (4TB each) to my Windows 7 64-bit PC - they are identical.

For identification purposes, let's call them Disk 1 and Disk 2.

Disk 1 is for storing images. Disk 2 will be a backup of Disk 1.

The intention is to leave Disk 1 in the PC and put Disk 2 in an external USB 3.0 enclosure (this one).

Here's what I've done so far:

Disk 1 is in the PC and (being larger than 2TB) has been initialised as GPT. It works fine, appears in Windows Explorer, and acts exactly as any other drive of 2TB or less would do - so I've copied 1.5TB of images onto it.​

To create the backup more quickly, I put Disk 2 into another bay in the PC and initialised it as GPT. The drive also appeared in Windows Explorer so I copied the contents of Disk 1 onto it. I then removed it from the PC and put it into the USB 3.0 enclosure. This time it did not appear in Windows Explorer. It was present in Disk Management but was showing as unallocated - i.e. not being initialised. The only way I can get it working in the enclosure is to initialise it again (as GPT) and re-copy all the data from Disk 1 - which takes hours.​

So, my question is: why does a drive that's already been initialised in the PC need to be initialised again when it's put into the USB 3.0 enclosure?

2798-1392301270-c3fb026742a58733ef652d51df929656.jpg


NB. Obviously, both drives were formatted (in Disk Management) after being initialised. My motherboard has UEFI, hence it supports disks larger than 2TB.
 
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does the caddy have any limitations on HDD size or formats that it accepts?
if it's USB3 I presume it's pretty much up to date and top end
 
DizMatt said:
does the caddy have any limitations on HDD size or formats that it accepts?
Click to expand...

No, the caddy has been tested by the manufacturer with two drives of 4TB each (as shown here). Drives can be RAID 0, RAID 1 or JBOD. I've got them set to JBOD. The caddy is connected to the PC via a USB 3.0 port.
 
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sounds like the caddy is causing the machine to think its a different disk.

edit - in fact it will do, startech multi drive enclosure will show the drive up as a different device. the underlying handling of the drive(s) i.e. raid/jbod may even have a different underlying drive type even if the partitions are formatted as ntfs (etc) later.

if that makes sense.
 
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Neil has just posted a reply before I finished typing mine.

foiled again :D
 
Agree with Neil_g, the caddy will show the drive maybe differently to how it was originally from the motherboard.
 
neil_g said:
sounds like the caddy is causing the machine to think its a different disk.

edit - in fact it will do, startech multi drive enclosure will show the drive up as a different device. the underlying handling of the drive(s) i.e. raid/jbod may even have a different underlying drive type even if the partitions are formatted as ntfs (etc) later.

if that makes sense.
Click to expand...

You've lost me there Neil.

Do you mean the Startech itself is acting as an extra device in between the PC and the 4TB Disk 2?
 
onomatopoeia said:
Neil has just posted a reply before I finished typing mine.

foiled again :D
Click to expand...
:p

Ozei said:
You've lost me there Neil.

Do you mean the Startech itself is acting as an extra device in between the PC and the 4TB Disk 2?
Click to expand...

yes.

heres a pictorial example :D

drives_zps292c2afb.jpg


in my server i have 2 multi drive enclosures, the AMD 4+0 and the HzW (this is a startech incidentally). the VB0250 is a normal internal drive.

if i moved the VB0250 into one of the multi drive enclosures you wouldnt see it as that any more, itd be folded into the AMD 4+0 or HzW for example.

windows has essentially seen it as a new drive ID and wants to initialise it.
 
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I think if it had been an ordinary caddy, you would have been fine (and had a goodly amount of spare cash in your pocket) :rolleyes:
 
neil_g said:
yes.

heres a pictorial example :D

drives_zps292c2afb.jpg


in my server i have 2 multi drive enclosures, the AMD 4+0 and the HzW (this is a startech incidentally). the VB0250 is a normal internal drive.

if i moved the VB0250 into one of the multi drive enclosures you wouldnt see it as that any more, itd be folded into the AMD 4+0 or HzW for example.

windows has essentially seen it as a new drive ID and wants to initialise it.
Click to expand...

So does this happen with all external enclosures?

Mikesphotaes said:
I think if it had been an ordinary caddy, you would have been fine (and had a goodly amount of spare cash in your pocket) :rolleyes:
Click to expand...

What do you mean by an ordinary caddy?
 
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True, I would just have a part 2 on another 4Tb and do away with any RAID problems though.

8Tb is a lot to lose if the NAS goes boobies up:eek:
 
Ozei said:
So does this happen with all external enclosures?
Click to expand...

What do you mean by an ordinary caddy?
Click to expand...

he means a single drive caddy. most single drive caddys just pass through the disk inside its hardware ID etc.

the fact that the startech does raid etc means it has a separate more advanced drive controller within it (like you would on a motherboard) which causes different hardware ID to be passed.
 
neil_g said:
which is why you always back a RAID up.
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Not just a RAID (I know it's your hobby horse though, Neil);)

I have been tempted by RAID etc. but so far have plodded along with numerous HDD all over the place.
 
neil_g said:
he means a single drive caddy. most single drive caddys just pass through the disk inside its hardware ID etc.

the fact that the startech does raid etc means it has a separate more advanced drive controller within it (like you would on a motherboard) which causes different hardware ID to be passed.
Click to expand...

Ah, I see.
Mikesphotaes said:
Probably should have said docking station....

http://www.ebuyer.com/336975-hard-drive-dock-3-5-2-5-usb-3-0-esata-56137/

...or a caddy that you can hotplug in one of your computer bays.
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Ah, I see (again :D). The reason I went for the Startech is because it's dual-bay and is easier to carry than two single-bay caddies. I wasn't interested in its RAID facility.
 
coming back into this.....that's not a caddy!
that's a NAS RAID enclosure!

The device will want to format it in a way that will be acceptable to RAID etc.
if you just had a USB caddy that would be a different kettle of fish!
 
Fair enough. I have a similar one and assume of you're going raid then you might as well have NAS capabilities.
Either way there is a raid controller board in there trying to be helpful
 
I've just done a test which may or may not confuse things again.

The Startech already contained a 2TB drive (i.e. it was already being used in the caddy before I added the 4TB).

So I've just done this:

1. Take the 2TB drive out of the Startech and put it in the PC. It appears in Windows Explorer and behaves as normal.
2. Take the 4TB drive (aka Disk 2) out of the Startech and put it in the PC. It does not appear in Windows Explorer and shows as unallocated in Disk Management.​

So, this is the conclusion:

Drives of 2TB or less that have MBR are swappable between the Startech and the PC - without doing anything.
Drives of 4TB that have GPT are not swappable between the Startech and the PC - they can only be read in the place they were initialised.
 
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Ozei said:
I've just done a test which may or may not confuse things again.

The Startech already contained a 2TB drive (i.e. it was already being used in the caddy before I added the 4TB).

So I've just done this:

1. Take the 2TB drive out of the Startech and put it in the PC. It appears in Windows Explorer and behaves as normal.
2. Take the 4TB drive (aka Disk 2) out of the Startech and put it in the PC. It does not appears in Windows Explorer and shows as unallocated in Disk Management.​

So, this is the conclusion:

Drives of 2TB or less that have MBR are swappable between the Startech and the PC - without doing anything.
Drives of 4TB that have GPT are not swappable between the Startech and the PC - they can only be read in the place they were initialised.
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may make sense. in JBOD mode it may pass through like a normal enclosure. so MBR may work correctly.

im not 100% sure but i think GPT uses some hardware IDs so if this is being generated using the motherboard controller then moved to the startech controller the GUID in the GPT may mismatch?

in which case you may well still have this problem with some single drive caddys.
 
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neil_g said:
may make sense. in JBOD mode it may pass through like a normal enclosure. so MBR may work correctly.

im not 100% sure but i think GPT uses some hardware IDs so if this is being generated using the motherboard controller then moved to the startech controller the GUID in the GPT may mismatch?

in which case you may well still have this problem with some single drive caddys.
Click to expand...

That would definitely explain everything. I've done a quick Google on it but can't find anything except gobbledegook.
 
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