4 primary disk partitions; none spare to extend, what to do

/dev/dog · 01-12-2015, 06:33 AM

Quote:

Originally Posted by Diantre

A MBR partition table can only have 4 primary partitions (if one of the primary partitions is an extended partition, it would be able to hold inside more partitions). A GPT partition table can hold 128 partitions. My guess is that you have a GPT disk with a protective MBR.

Could you post the output of these commands? (replace sdX with the correct location of your disk)

Code:

# fdisk -l /dev/sdX
# gdisk -l /dev/sdX

...

Hi Diantre

From the thread I started, I gathered that my hd is also formatted with a GPT and a protective MBR. My follow up questions probably belongs in a windows forum, I wanted to know why Windows reported those partitions as primaries. (You can see a screenshot in my thread here)

Code:

alpha@dogpack05:~$ sudo fdisk -l /dev/sda

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x34dde5f9

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      718847      358400    7  HPFS/NTFS/exFAT           #GRUB
/dev/sda2          718848   537589759   268435456    7  HPFS/NTFS/exFAT           #Windows 8.1
/dev/sda3       537589760   545978367     4194304   83  Linux                     #/
/dev/sda4       545980414   976771071   215395329    f  W95 Ext'd (LBA)           # HAHA! Extended partition!
Partition 4 does not start on physical sector boundary.
/dev/sda5       545980416   579534847    16777216   83  Linux                     #/usr
/dev/sda6       579536896   587925503     4194304   83  Linux                     #/var
/dev/sda7       587927552   722145279    67108864   83  Linux                     #/home
/dev/sda8       943216640   976771071    16777216   82  Linux swap / Solaris      #swap

(I added comments to the above code identifying each partition)

Code:

alpha@dogpack05:~$ sudo gdisk -l /dev/sda
GPT fdisk (gdisk) version 0.8.5

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


***************************************************************
Found invalid GPT and valid MBR; converting MBR to GPT format.
***************************************************************

Disk /dev/sda: 976773168 sectors, 465.8 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 9FCA6F86-FF3B-4DA9-921A-60BA380241F4
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 976773134
Partitions will be aligned on 2048-sector boundaries
Total free space is 221081581 sectors (105.4 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048          718847   350.0 MiB   0700  Microsoft basic data
   2          718848       537589759   256.0 GiB   0700  Microsoft basic data
   3       537589760       545978367   4.0 GiB     8300  Linux filesystem
   5       545980416       579534847   16.0 GiB    8300  Linux filesystem
   6       579536896       587925503   4.0 GiB     8300  Linux filesystem
   7       587927552       722145279   64.0 GiB    8300  Linux filesystem
   8       943216640       976771071   16.0 GiB    8200  Linux swap

Diantre · 01-12-2015, 01:18 PM

Quote:

Originally Posted by /dev/dog

From the thread I started, I gathered that my hd is also formatted with a GPT and a protective MBR. My follow up questions probably belongs in a windows forum, I wanted to know why Windows reported those partitions as primaries.

It seems that your disk is a MBR disk, it doesn't have a GPT partition table on it. Your disk has 4 primary partitions, the fourth partition is extended and contains four other partitions. It looks like an absolutely normal MBR disk to me.

Compare the output you got from fdisk with my output. In my system fdisk reports:

Code:

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.

...

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1  1953525167   976762583+  ee  GPT

That's how fdisk sees a GPT disk, just one single partition of type EE. And the error message at the start is quite clear. In your system, fdisk can "see" the partition table without any problems. That should give you the answer: it's a MBR disk.

The gdisk utility also tells you the same thing:

Quote:

Originally Posted by /dev/dog

Code:

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

If your disk was a GPT disk with a protective MBR, gdisk would say something like this:

Code:

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

Followed by the list of partitions on the disk.

I forgot to mention the parted utility in my previous post, but in your other thread you already used it:

Quote:

Originally Posted by /dev/dog

Code:

alpha@dogpack05:~$ sudo parted -l
Model: ATA WDC WD5000BPKX-2 (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos

Number  Start   End    Size    Type      File system     Flags
 1      1049kB  368MB  367MB   primary   ntfs            boot
 2      368MB   275GB  275GB   primary   ntfs
 3      275GB   280GB  4295MB  primary   ext4
 4      280GB   500GB  221GB   extended                  lba
 5      280GB   297GB  17.2GB  logical   ext4
 6      297GB   301GB  4295MB  logical   ext4
 7      301GB   370GB  68.7GB  logical   ext4
 8      483GB   500GB  17.2GB  logical   linux-swap(v1)

The line to look for is "Partition Table: msdos", that indicates your disk is MBR. On a GPT disk, that line would read "Partition Table: gpt".

Well then, all three partitioning utilities (fdisk, gdisk and parted), report the same thing. The disk is MBR, not GPT.

business_kid · 01-13-2015, 04:00 AM

With the heatsinks on modern videl cards, I really wonder how those things would make out. These days there's a massive psu, and massive heatsinks on GPU & CPU. Good luck designing airflow into a briefcase.

/dev/dog · 01-14-2015, 06:58 AM

Quote:

Originally Posted by Diantre

It seems that your disk is a MBR disk, it doesn't have a GPT partition table on it. Your disk has 4 primary partitions, the fourth partition is extended and contains four other partitions. It looks like an absolutely normal MBR disk to me.
...
The line to look for is "Partition Table: msdos", that indicates your disk is MBR. On a GPT disk, that line would read "Partition Table: gpt".

Well then, all three partitioning utilities (fdisk, gdisk and parted), report the same thing. The disk is MBR, not GPT.

...

Hi Diantre

Thanks, both you and the other guy on my other thread were helpful. I was alarmed because of Windows GUI telling me there were more than 4 primary partitions; I ran here to confirm if I am going insane or if an MBR can have more than 4 primary partitions. Turns out it was a third conclusion - Microsoft lied to me.

Thanks