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[speedyarmadillo]

Does DNS-320L format a 3TB internal HDD as GPT or MBR?

I can not find anything that specifically says it uses GPT or MBR on drives, and I can not find anything in the manual that gives an option to specify either one or boot in that manner, so I am wondering what it formats HDDs to?

My uncertainty is fueled by the fact that MBR has an official limit of 2TB, but apparently Linux can use a few tricks to go beyond this limit, so I was wondering that being as the 320L uses Linux if it uses any of the Linux "tricks" to use MBR on 3TB HDDs or if it automatically uses GPT (or for that matter formats all HDDs it is given as GPT)?

To add to my confusion, I thought I saw firmware release notes saying that the 320L will support GPT on USB external drives, but no mention of the internal drives (and I do not know where I saw it).

Lastly, if the answer to the above question is that the 320L does not natively format internal HDDs as GPT, is there way I can force a GPT HDD on it by first formatting it as GPT in a Linux PC before installing them in the 320L, etc?

[cable2]

Hi,
I am sure, that it uses neither.  These things are basically linux boxes and use either ext3 or ext4.  GPT / MBR are not applicable.

[speedyarmadillo]

Hi Cable2.  I believe that EXT4 and MBR/GPT not mutually exclusive, as they are separate things.

My understanding is that on PC hardware, MBR/GPT is the partition scheme used on the HDD, and EXT4 is the format used within the MBR or GPT partition scheme.  So on PC hardware you can format a HDD as EXT4 in either MBR or GPT, but you do have to choose one or the other of MBR or GPT.  What I don't know is if the DNS-320L has the same limitations as PC hardware being as the 320L is specialized custom hardware (maybe different limitations apply than just the PC hardware BIOS or UEFI options?), but my guess is that they would have stuck with MBR or GPT regardless otherwise you would not be able to remove a HDD from a 320L and put it in a Linux PC to read the drive if you wanted to (which I am pretty sure you can do).

Therefore I am pretty sure the 320L has to partition the HDD as either MBR or GPT, irrespective of formatting as EXT4.

Anyone care to shed light on this?

[ivan]

The real question is, does it matter?

Both MBR and GPT are systems for tracking multiple partitions on a hard drive for the information of the operating system and since most NAS only use one partition and don't have an operating system installed on the disk - the OS is installed in the firmware of the SoC - most of the MBR/GPT information is redundant and not used.

To answer your initial question

Does DNS-320L format a 3TB internal HDD as GPT or MBR?

  No it formats as Ext3,4.  As to how it handles the partition information I don't know and can't be bothered to look at the firmware source code to find out because it is built into the firmware and can't be changed.

[speedyarmadillo]

Hi Ivan.  You seem to have had a bad day as your reply seemed a bit peevish.  But to answer your question, yes, it does matter to some people, but clearly not yourself.  GPT has advantages over MBR, as GPT is fault-tolerance by keeping copies of the partition table in the first and last sector on the disk, and GPT computes a CRC to verify its own integrity, and of the partition table.  More robust than MBR, and of course robust is the whole reason to use a NAS with RAID1 in the first place so if I have a choice I will take more robust over less robust any day.

As to your narrow interpretation of my question, yes, EXT4 is the filesystem format, but MBR/GPT is the partitioning format, and since I have not seen any other term but format used when referring to choosing MBR or GPT, I used it as well, but heck, if you have some personal preference for another term feel free to use that instead.

So my initial questions still hold (although I will make it simpler this time):
1) does anyone know if the 320L formats the HDDs with "EXT4 on GPT", or "EXT4 on MBR" when using 3TB discs?
2) if the answer to the above is MBR, then does anyone know if I pre-format the HDDs as "EXT4 on GPT" before putting them into a DNS-320L, will the 320L recognize and accept them happily (in RAID1)?

Thanks in advance to anyone who can help.

[ivan]

Sorry if I sounded a bit peevish, it was 01:10 in the morning local time and I had started work at 06:30 local time the previous day.

I'm sorry but we don't have the L version here or with any of our clients and my programmer is on holiday so I can't do a physical check to find out.

To answer your point 2.  We have never been able to get the standard DNS-320 to accept preformatted drives at all - they insist on doing the formatting in the unit.

Other than that I can't say more.

[cable2]

Hi Speedy,
I can tell you are both smart and knowledgeable but perhaps in your haste to get the help you were looking for, you apparently missed the fact that you posted your request in the wrong forum.  The 320L is the new version.  To be truthful though, most of the questions in these forums are from "basic" users and the answers are from folks with one or two more fingers than the rest of the "lepers".  A highly technical question such as yours would probably be best directed at Dlink Support via phone or email.  Another far simplier and quicker answer would probably best be found by installing a hard drive in your 320L and after the initial format is complete, pull it and check the drive in one of your Linux machines to determine exactly how it is partitioned.  If this is a pre-purchase question, then maybe you could ask for someone in the 320L forum to do this for you.  Good luck.

[JavaLawyer]

Hi Speedy,
I can tell you are both smart and knowledgeable but perhaps in your haste to get the help you were looking for, you apparently missed the fact that you posted your request in the wrong forum.  The 320L is the new version. . .

I'll move this thread to the DNS-320L board...

[pizzaking]

I have two 3TB disks in mine, and they are both GPT formated by the 320L. The output from gdisk -l /dev/sda looks like this:

Code: [Select]

GPT fdisk (gdisk) version 0.6.13

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/sda: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 1AB41C94-0721-46DA-A425-7CBCCE87F61B
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 3186 sectors (1.6 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048         1050623   512.0 MiB   8200  Linux swap
   2         3147776      5858433899   2.7 TiB     0700  Linux/Windows data
   3      5858435072      5860533134   1.0 GiB     0700  Linux/Windows data
   4         1050624         3147775   1024.0 MiB  0700  Linux/Windows data


[speedyarmadillo]

Thank you all very much for the help.
Ivan, thank you for the information on the pre-formatted HDD question as that is very useful and will have saved me a lot of effort if I ever chose to try that path in the future.

Java Lawyer, thank you for moving the thread to the correct forum.  Honestly, before posting my question I looked all over the forums and did not see a 320L board anywhere (except a child board under the camera section, which did not seem the right place being as it was not a camera question), so clearly I completely missed something.  I do not even have the reasonable excuse of being too tired or too hasty, as I just somehow completely missed the correct place to post it.  Sorry about that.

Pizzaking, thank you for your post as it completely answers my questions.

Thanks again, as it really is very much appreciated.

[JavaLawyer]

Java Lawyer, thank you for moving the thread to the correct forum.  Honestly, before posting my question I looked all over the forums and did not see a 320L board anywhere (except a child board under the camera section, which did not seem the right place being as it was not a camera question), so clearly I completely missed something.  I do not even have the reasonable excuse of being too tired or too hasty, as I just somehow completely missed the correct place to post it.  Sorry about that.

D-Link wanted all of the Cloud enabled devices grouped together, explaining why the DNS-320L was placed here rather than the ShareCenter section.