What is the difference between the Linux and Linux LVM partition type?

Question

Fdisk shows multiple partition types. What is the difference between choosing 83) Linux and 8e) Linux LVM?

Choosing 83) Linux also works fine for using LVM, even creating a physical volume on /dev/sdb without a partition table works.

Does picking a partition type in fdisk really matter? What is the difference in picking Linux or Linux LVM as partition type?

[root@tst-01 ~]# fdisk /dev/sdb

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): l

 0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris
 1  FAT12           39  Plan 9          82  Linux swap / So c1  DRDOS/sec (FAT-
 2  XENIX root      3c  PartitionMagic  83  Linux           c4  DRDOS/sec (FAT-
 3  XENIX usr       40  Venix 80286     84  OS/2 hidden C:  c6  DRDOS/sec (FAT-
 4  FAT16 <32M      41  PPC PReP Boot   85  Linux extended  c7  Syrinx
 5  Extended        42  SFS             86  NTFS volume set da  Non-FS data
 6  FAT16           4d  QNX4.x          87  NTFS volume set db  CP/M / CTOS / .
 7  HPFS/NTFS       4e  QNX4.x 2nd part 88  Linux plaintext de  Dell Utility
 8  AIX             4f  QNX4.x 3rd part 8e  Linux LVM       df  BootIt
 9  AIX bootable    50  OnTrack DM      93  Amoeba          e1  DOS access
 a  OS/2 Boot Manag 51  OnTrack DM6 Aux 94  Amoeba BBT      e3  DOS R/O
 b  W95 FAT32       52  CP/M            9f  BSD/OS          e4  SpeedStor
 c  W95 FAT32 (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi eb  BeOS fs
 e  W95 FAT16 (LBA) 54  OnTrackDM6      a5  FreeBSD         ee  GPT
 f  W95 Ext'd (LBA) 55  EZ-Drive        a6  OpenBSD         ef  EFI (FAT-12/16/
10  OPUS            56  Golden Bow      a7  NeXTSTEP        f0  Linux/PA-RISC b
11  Hidden FAT12    5c  Priam Edisk     a8  Darwin UFS      f1  SpeedStor
12  Compaq diagnost 61  SpeedStor       a9  NetBSD          f4  SpeedStor
14  Hidden FAT16 <3 63  GNU HURD or Sys ab  Darwin boot     f2  DOS secondary
16  Hidden FAT16    64  Novell Netware  af  HFS / HFS+      fb  VMware VMFS
17  Hidden HPFS/NTF 65  Novell Netware  b7  BSDI fs         fc  VMware VMKCORE
18  AST SmartSleep  70  DiskSecure Mult b8  BSDI swap       fd  Linux raid auto
1b  Hidden W95 FAT3 75  PC/IX           bb  Boot Wizard hid fe  LANstep
1c  Hidden W95 FAT3 80  Old Minix       be  Solaris boot    ff  BBT
1e  Hidden W95 FAT1

Command (m for help):

Answer 1

The partition type byte is just that, a single byte in the Partition Table that holds a value that should relate to the file system inside the associated partition. It's really just a hint of what methods the OS should try when attempting to read/mount the partition. If you didn't have this the system would need to try to read the partition using a number of types - and obviously it could get this wrong.

An analogy would be that if I read a phone number and it started with 001 or 044 I could start the conversion in English with a good chance of being understood from the start - it could be wrong but there's a good chance it would be ok. If it said 033 then I could assume that starting in French would be a good idea, 039 and I could try Italian first - and so on. Basically it's a strong-indicator, but only that - it can be wrong, of the underlying file system's type.

As to what the actual difference is between those two options - well that could go on to be a very long answer but essentially LVM deals with extents and has multiple additional layers of abstraction that clearly need to be considered during boot - whereas the standard Linux Partition Type should be a lot more straightforward than LVM for the OS to deal with. Either way the booting kernel would benefit from knowing what to try first.