LinuxQuestions.org - Partitions on LINUX

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Partitions on LINUX

I know its possible to create 4 primary partitions on LINUX

1) How many extended partition we can create maximum ?

2) How many Logical partitions we can create maximum ?

Actually the number of "partitions" isn't what it used to be. You can have buckets of them and it depends on the "label" or type of disk format you want to use. If you had a 16TB disk array which is presented as a single logical unit then you may want dozens of "slices" or "partitions". If we look at fdisk then list the known partition types we see a massive list :

1 EFI System C12A7328-F81F-11D2-BA4B-00A0C93EC93B
2 MBR partition scheme 024DEE41-33E7-11D3-9D69-0008C781F39F
3 Intel Fast Flash D3BFE2DE-3DAF-11DF-BA40-E3A556D89593
4 BIOS boot 21686148-6449-6E6F-744E-656564454649
5 Sony boot partition F4019732-066E-4E12-8273-346C5641494F
6 Lenovo boot partition BFBFAFE7-A34F-448A-9A5B-6213EB736C22
7 PowerPC PReP boot 9E1A2D38-C612-4316-AA26-8B49521E5A8B
8 ONIE boot 7412F7D5-A156-4B13-81DC-867174929325
9 ONIE config D4E6E2CD-4469-46F3-B5CB-1BFF57AFC149
10 Microsoft reserved E3C9E316-0B5C-4DB8-817D-F92DF00215AE
11 Microsoft basic data EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
12 Microsoft LDM metadata 5808C8AA-7E8F-42E0-85D2-E1E90434CFB3
13 Microsoft LDM data AF9B60A0-1431-4F62-BC68-3311714A69AD
14 Windows recovery environment DE94BBA4-06D1-4D40-A16A-BFD50179D6AC
15 IBM General Parallel Fs 37AFFC90-EF7D-4E96-91C3-2D7AE055B174
16 Microsoft Storage Spaces E75CAF8F-F680-4CEE-AFA3-B001E56EFC2D
17 HP-UX data 75894C1E-3AEB-11D3-B7C1-7B03A0000000
18 HP-UX service E2A1E728-32E3-11D6-A682-7B03A0000000
19 Linux swap 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F
20 Linux filesystem 0FC63DAF-8483-4772-8E79-3D69D8477DE4
21 Linux server data 3B8F8425-20E0-4F3B-907F-1A25A76F98E8
22 Linux root (x86) 44479540-F297-41B2-9AF7-D131D5F0458A
23 Linux root (ARM) 69DAD710-2CE4-4E3C-B16C-21A1D49ABED3
24 Linux root (x86-64) 4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709
25 Linux root (ARM-64) B921B045-1DF0-41C3-AF44-4C6F280D3FAE
26 Linux root (IA-64) 993D8D3D-F80E-4225-855A-9DAF8ED7EA97
27 Linux reserved 8DA63339-0007-60C0-C436-083AC8230908
28 Linux home 933AC7E1-2EB4-4F13-B844-0E14E2AEF915
29 Linux RAID A19D880F-05FC-4D3B-A006-743F0F84911E
30 Linux extended boot BC13C2FF-59E6-4262-A352-B275FD6F7172
31 Linux LVM E6D6D379-F507-44C2-A23C-238F2A3DF928
32 FreeBSD data 516E7CB4-6ECF-11D6-8FF8-00022D09712B
33 FreeBSD boot 83BD6B9D-7F41-11DC-BE0B-001560B84F0F
34 FreeBSD swap 516E7CB5-6ECF-11D6-8FF8-00022D09712B
35 FreeBSD UFS 516E7CB6-6ECF-11D6-8FF8-00022D09712B
36 FreeBSD ZFS 516E7CBA-6ECF-11D6-8FF8-00022D09712B
37 FreeBSD Vinum 516E7CB8-6ECF-11D6-8FF8-00022D09712B
38 Apple HFS/HFS+ 48465300-0000-11AA-AA11-00306543ECAC
39 Apple UFS 55465300-0000-11AA-AA11-00306543ECAC
40 Apple RAID 52414944-0000-11AA-AA11-00306543ECAC
41 Apple RAID offline 52414944-5F4F-11AA-AA11-00306543ECAC
42 Apple boot 426F6F74-0000-11AA-AA11-00306543ECAC
43 Apple label 4C616265-6C00-11AA-AA11-00306543ECAC
44 Apple TV recovery 5265636F-7665-11AA-AA11-00306543ECAC
45 Apple Core storage 53746F72-6167-11AA-AA11-00306543ECAC
46 Solaris boot 6A82CB45-1DD2-11B2-99A6-080020736631
47 Solaris root 6A85CF4D-1DD2-11B2-99A6-080020736631
48 Solaris /usr & Apple ZFS 6A898CC3-1DD2-11B2-99A6-080020736631
49 Solaris swap 6A87C46F-1DD2-11B2-99A6-080020736631
50 Solaris backup 6A8B642B-1DD2-11B2-99A6-080020736631
51 Solaris /var 6A8EF2E9-1DD2-11B2-99A6-080020736631
52 Solaris /home 6A90BA39-1DD2-11B2-99A6-080020736631
53 Solaris alternate sector 6A9283A5-1DD2-11B2-99A6-080020736631
54 Solaris reserved 1 6A945A3B-1DD2-11B2-99A6-080020736631
55 Solaris reserved 2 6A9630D1-1DD2-11B2-99A6-080020736631
56 Solaris reserved 3 6A980767-1DD2-11B2-99A6-080020736631
57 Solaris reserved 4 6A96237F-1DD2-11B2-99A6-080020736631
58 Solaris reserved 5 6A8D2AC7-1DD2-11B2-99A6-080020736631
59 NetBSD swap 49F48D32-B10E-11DC-B99B-0019D1879648
60 NetBSD FFS 49F48D5A-B10E-11DC-B99B-0019D1879648
61 NetBSD LFS 49F48D82-B10E-11DC-B99B-0019D1879648
62 NetBSD concatenated 2DB519C4-B10E-11DC-B99B-0019D1879648
63 NetBSD encrypted 2DB519EC-B10E-11DC-B99B-0019D1879648
64 NetBSD RAID 49F48DAA-B10E-11DC-B99B-0019D1879648
65 ChromeOS kernel FE3A2A5D-4F32-41A7-B725-ACCC3285A309
66 ChromeOS root fs 3CB8E202-3B7E-47DD-8A3C-7FF2A13CFCEC
67 ChromeOS reserved 2E0A753D-9E48-43B0-8337-B15192CB1B5E
68 MidnightBSD data 85D5E45A-237C-11E1-B4B3-E89A8F7FC3A7
69 MidnightBSD boot 85D5E45E-237C-11E1-B4B3-E89A8F7FC3A7
70 MidnightBSD swap 85D5E45B-237C-11E1-B4B3-E89A8F7FC3A7
71 MidnightBSD UFS 0394EF8B-237E-11E1-B4B3-E89A8F7FC3A7
72 MidnightBSD ZFS 85D5E45D-237C-11E1-B4B3-E89A8F7FC3A7
73 MidnightBSD Vinum 85D5E45C-237C-11E1-B4B3-E89A8F7FC3A7
74 Ceph Journal 45B0969E-9B03-4F30-B4C6-B4B80CEFF106
75 Ceph Encrypted Journal 45B0969E-9B03-4F30-B4C6-5EC00CEFF106
76 Ceph OSD 4FBD7E29-9D25-41B8-AFD0-062C0CEFF05D
77 Ceph crypt OSD 4FBD7E29-9D25-41B8-AFD0-5EC00CEFF05D
78 Ceph disk in creation 89C57F98-2FE5-4DC0-89C1-F3AD0CEFF2BE
79 Ceph crypt disk in creation 89C57F98-2FE5-4DC0-89C1-5EC00CEFF2BE
80 OpenBSD data 824CC7A0-36A8-11E3-890A-952519AD3F61
81 QNX6 file system CEF5A9AD-73BC-4601-89F3-CDEEEEE321A1
82 Plan 9 partition C91818F9-8025-47AF-89D2-F030D7000C2C

If you mean a DOS style PC ( a small x86 personal computer ) then usually the partition is a DOS type and therein you can only have four primary partitions which are non-overlapping cylinder groups. However there are piles of ways to partition a disk or storage logical unit.

On MBR:
One extended, it has to be one of the four primary partitions, and serves as a container for logical partitions.
I'm not aware of any limit on the number of logical partitions.

Note that none of these restrictions has to do with Linux, these are simply restrictions of the MBR partition table. Windows has the same restrictions when using MBR. If you switch to GPT I don't believe it has any of these restrictions.

If you use GPT, then you can have 128 partitions.
With MBR, there's no theoretical limit on logical partitions.

Hi,

T am NOT getting exactly.
I am using OEL 5.5 and OEL 6.8

I have only one Primary partition. --> /dev/sdb

1) on /dev/sdb ------> How many extended partition i can make ?
2) IS there any difference between Logical Partition and Extended Partition ?

/dev/sdb is not a partition, /dev/sdb is a drive. /dev/sdb1, /dev/sdb2, /dev/sdb3, etc. would be the partitions on that drive.

1) One, as I said above. You can create one extended partition, and it must be one of the four primaries.
2) Yes, as I said above. You can create one extended partition, as a primary, and that extended partition is then used as a container inside which you can create as many logical partitions as you want.

Hi,

Thanks for reply.
One more question

/dev/sdb1
/dev/sdb2
/dev/sdb3

1) are they called as 'block devices or raw devices' ?
2) If the drive is NOT partitioned (/dev/sdb) , can we call that disk as 'raw disk' ?

In the hope that it might be of some use, my blog post on partitions:

http://www.linuxquestions.org/questi...-vs-gpt-37329/

Hi,

What i understood, Without creating Extended partition we cannot create logical partition.
Primary partition is not always required.

Is there any limit to create extended partition ? - i think maximum we can create only 1 extended partition.

PHP Code:




Command (m for help): n 
Command action 
   e   extended 
   p   primary partition (1-4) 
e 
Partition number (1-4): 1 
First cylinder (1-2610, default 1): 
Using default value 1 
Last cylinder or +size or +sizeM or +sizeK (1-2610, default 2610): 100 
 
Command (m for help): n 
Command action 
   l   logical (5 or over) 
   p   primary partition (1-4)

Quote:

Originally Posted by Joy Stick (Post 5743316)

1) No, these are all partitions.

2) Yes, you could call it that. However, the disk could have partitions and you could still access /dev/sdb as a raw disk (although this would be only advisable with care).

Quote:

Originally Posted by Joy Stick (Post 5743371)

PHP Code:




Command (m for help): n 
Command action 
   e   extended 
   p   primary partition (1-4) 
e 
Partition number (1-4): 1 
First cylinder (1-2610, default 1): 
Using default value 1 
Last cylinder or +size or +sizeM or +sizeK (1-2610, default 2610): 100 
 
Command (m for help): n 
Command action 
   l   logical (5 or over) 
   p   primary partition (1-4)

Note that this answer refers to the MBR partitioning scheme. GPT is more flexible and powerful as regards the number of partitions.

MBR allows 4 primary partitions, which are numbered 1-4 whether they are used or not. One of these can hold a placeholder extended partition containing a linked list of logical partitions, for which the numbering starts at 5. Theoretically you can have an unlimited number of logical partitions.

Quote:

If first starts with 'b' means, it is a block device - am i right ?

PHP Code:




# ls -l /dev/sdb* 
brw-r----- 1 root disk 8, 16 Aug  3 03:43 /dev/sdb 
brw-r----- 1 root disk 8, 17 Aug  3 03:43 /dev/sdb1

PHP Code:




# cat /proc/partitions 
major minor  #blocks  name 
 
   8     0   78643200 sda 
   8     1     104391 sda1 
   8     2   25599577 sda2 
   8     3   10241437 sda3 
   8     4          1 sda4 
   8     5    2867571 sda5 
   8     6    1534176 sda6 
   8     7   38290896 sda7 
   8    16   10485760 sdb 
   8    17   10482381 sdb1 
   8    32   10485760 sdc 
   8    33   10482381 sdc1 
   8    48   10485760 sdd 
   8    49   10482381 sdd1 
   8    64   10485760 sde 
   8    65   10482381 sde1 
   8    80   20971520 sdf

2) I want to know exactly what is mapped internally /sda1 - sda7 ?
3) How do i check it out ?

Quote:

Originally Posted by Joy Stick (Post 5743387)

PHP Code:




# ls -l /dev/sdb* 
brw-r----- 1 root disk 8, 16 Aug  3 03:43 /dev/sdb 
brw-r----- 1 root disk 8, 17 Aug  3 03:43 /dev/sdb1

PHP Code:




# cat /proc/partitions 
major minor  #blocks  name 
 
   8     0   78643200 sda 
   8     1     104391 sda1 
   8     2   25599577 sda2 
   8     3   10241437 sda3 
   8     4          1 sda4 
   8     5    2867571 sda5 
   8     6    1534176 sda6 
   8     7   38290896 sda7 
   8    16   10485760 sdb 
   8    17   10482381 sdb1 
   8    32   10485760 sdc 
   8    33   10482381 sdc1 
   8    48   10485760 sdd 
   8    49   10482381 sdd1 
   8    64   10485760 sde 
   8    65   10482381 sde1 
   8    80   20971520 sdf

2) I want to know exactly what is mapped internally /sda1 - sda7 ?
3) How do i check it out ?

df will show you where your partitions are mounted.

Here some partitions are missing.
/sda4, sda6 - where are they ? How do i check ?

PHP Code:




# df -TH 
Filesystem    Type     Size   Used  Avail Use% Mounted on 
/dev/sda3     ext3      11G   5.1G   4.6G  53% / 
/dev/sda7     ext3      38G   1.3G    35G   4% /u02 
/dev/sda5     ext3     2.9G   1.9G   886M  68% /tmp 
/dev/sda2     ext3      26G    11G    14G  43% /u01 
/dev/sda1     ext3     104M    12M    87M  12% /boot 
tmpfs        tmpfs     530M      0   530M   0% /dev/shm 
.host:/     vmhgfs      47G    25G    23G  53% /mnt/hgfs

@ hydrurga

You told /dev/sdb1 are partitions and not block devices
If first letter starts with 'B' - they are block devices. - AM I RIGHT ?

PHP Code:




# ls -l /dev/sdb* /dev/sdc* 
brw-r----- 1 root disk 8, 16 Aug  3 03:43 /dev/sdb 
brw-r----- 1 root disk 8, 17 Aug  3 03:43 /dev/sdb1 
brw-r----- 1 root disk 8, 32 Aug  3 03:43 /dev/sdc 
brw-r----- 1 root disk 8, 33 Aug  3 03:43 /dev/sdc1

You can use "fdisk -l /dev/sda" to check sda's partition table to see if those other partitions exist and what type they are. If they exist, you can attempt to mount them in a directory of your choosing.

I think you need to back up and tell us what it is you're trying to accomplish here though. With a more focused discussion we'd be able to provide much more applicable and accurate advice.