GUID Partition Table without Microsoft Partition

[j7n]

I have a 4TB disk and want to create one partition spanning the whole disk. If I go to Disk Management and do Initialize Disk, Convert to GUID Partition Table, Format, it also creates a hidden Microsoft Reserved Partition of 128 MB. I tried formatting the disk with BOOTICE. While the partition mounts and is visible in explorer intially, it is invisible to Disk Management, and doesn't work after a reboot. The disk is shown as uninitialized again. Is it possible to format this disk without the hidden partition?

I previously formatted with BOOTICE just fine, but it is the first time I need to use the GUID format because the disk is too big.

Server 2003.

Edited November 12, 2022 by j7n

[jaclaz]

gdisk?

https://www.rodsbooks.com/gdisk/

jaclaz

[j7n]

This program worked. I enjoyed reading the extensive knowledge base on rodsbooks.com. In one section it mentioned not partitioning a disk as an option for large disks. Is it possible to have a filesystem on a disk in Windows without a partition table?

[jaclaz]

53 minutes ago, j7n said:

This program worked. I enjoyed reading the extensive knowledge base on rodsbooks.com. In one section it mentioned not partitioning a disk as an option for large disks. Is it possible to have a filesystem on a disk in Windows without a partition table?

Yes and no, maybe it is possible, maybe not and it will probably depend on the exact windows OS.

Once upon a time most USB sticks were partitionless, i.e. they were initialized as super-floppies.

Then we started wanting partitions on them (for one reason or the other) and though we found our ways, for several releases Windows would only mount the first partition if the device was set as "removable", and "special" filter drivers were developed to allow mounting all volumes/partitions on removable devices.

Windows 10 has changed in this regard when compared to previous versions, and AFAIK doesn't make a distinction between partitioned and unpartitioned removable devices (i.e. it shows all partitions on removable device anyway), how it behaves with "fixed" devices has to be seen, it is entirely possible that a "fixed" disk device needs to be partitioned.

It is possible that a "reversed" filter driver is needed.

BUT (in case of need) one could use IMDISK to map an extent of the physicaldrive to a volume (of course not for boot drives).

jaclaz

P.S::

I doubt that the 128 MB partition is actually invisible in Disk Manager, in the sense that (given that the "other" partition is very large) likely it is too "thin" to be shown, there is a setting somewhere in the interface of diskmanager to make it show all partitions the same width (regardless of their size in bytes), you should try that option

Edited November 12, 2022 by jaclaz

[D.Draker]

I got rid of small 4Tb disks long time ago, but when I format 8Tb as GPT - I don't get that weird partition. On Vista.

XP and 7 just love to make them, esp. when you install a system from scratch and forgot to switch off all HDDs,

except the system one. Server 2003 behaves the same way as XP in this regard.

[j7n]

I see it in View->Settings. By default they are sized to logarithmic scale. The partition is completely invisible to the Disk Manager. I feel like it's a waste. It would be cool if that space could be loaded with DOS utilities, which can't access any other NTFS disk, but it seems to serve no purpose at all.

Is 4TB "small" already?

[jaclaz]

It is strange, maybe it is something "peculiar" to Server 2003 that prevents a particular partition ID to be shown, anyway good to know .

With gdisk you can change he partition ID to a "normal" volume and then format it  as FAT, can't you?

But DOS won't ever be able to access it (being on a GPT style disk), so it would be only an exercise in futility, unless you enter the rabbit hole (which is veeeery deep) and use something like grub4dos to map the extent in real mode to a virtual disk, not really worth it unless you have some queer needs to semi-hide that volume (a plain RAW image file would do the same with less complications).

From the little I know about that MS reserved partition, it is only used by some windows versions (probably not even 2003 and 7, more likely 8+) as a sort of cache when resizing (other) volumes, so I believe it is OK to just remove it and make the volume start earlier.

Anyway there is something else that is "uncommon", it seems like that MS Reserved partition starts on sector LBA 34 (i.e. right after the protective MBR+GPT header+GPT partition table, 1+1+32) whilst normally any Vista or later Windows would align to 1 MB, i.e. first partition would always start on sector LBA 2048.

Your "main" partition is starting on LBA 262178, so that one seems fine is also NOT MB aligned, it is entirely possible that we are used to see also the MS reserved partition MB aligned because it is mostly the second partition, after the UEFI boot one, but in itself it is ignored by the "force to MB alignment" algorithm, another interesting thing to know..

To be "kosher",  it would IMHO be advisable to have the large partition start on LBA 2048, though it is not like there will be any bettering in speed or performance that could be noticeable, but probably some software that expects MB alignment might not "like" the current offset.

Personally (but mind you besides being a grumpy bastard I am an old one) the sheer idea of having such large volumes is pure folly and I would personally divide that 4 TB into much smaller volumes (and I wouldn't normally even touch 8 TB disks) but for data storage/backup such huge volumes may be fine, only when (if) you might need to make dd copies or attempt to recover data from them it will take about forever.

jaclaz

 

Edited November 13, 2022 by jaclaz
corrected wrong assumption that second partition was MB aligned

[D.Draker]

On 11/13/2022 at 4:20 AM, j7n said:

Is 4TB "small" already?

Yes. It's not even 4tb. It's 3,5 or so, scam as usual, with their "clever" calculations, and 10TB will be 8Tb in reality.

On the other hand, maybe enough for avi potato qiality vids, even today.

Got myself a 6tb in 2019 and it became 5.4 after firmatting . Scam. Then bought 8tb and it was only 7 with smth.

[Mov AX, 0xDEAD]

from wiki:

Quote

 

Formerly, on disks formatted using the master boot record (MBR) partition layout, certain software components used hidden sectors of the disk for data storage purposes. For example, the Logical Disk Manager (LDM), on dynamic disks, stores metadata in a 1 MB area at the end of the disk which is not allocated to any partition.^[3]

The UEFI specification does not allow hidden sectors on GPT-formatted disks. Microsoft reserves a chunk of disk space using this MSR partition type, to provide an alternative data storage space for such software components which previously may have used hidden sectors on MBR formatted disks.^[1] Such software components can create a small software-component specific partition from a portion of the space reserved in the MSR partition.

 

So MS may use this partition as blob without fillesystem and probably Disk Manager GUI hides it to keep metadata from destroying

[jaclaz]

1 hour ago, Mov AX, 0xDEAD said:

from wiki:

So MS may use this partition as blob without fillesystem and probably Disk Manager GUI hides it to keep metadata from destroying

Yes, it seems like it is listed in diskpart but invisible in disk manager, also in later Windows versions see the image here:

https://social.technet.microsoft.com/Forums/en-US/a0a64818-6150-40b4-b5b3-915eb8fe31c9/msr-reserved-partition-does-not-appear-in-disk-management-nor-in-my-backup-program?forum=w8itproinstall

jaclaz