- PARTITIONING
- Partitions are defined by data structures that are written to specific parts of the disk
- Several partitioning options are available
- MBR
- Master Boot Record (MBR) stores data on the first sector of the disk
- MBR uses up to four primary partitions, or three primary and one extended partition
- Partition Options:
- Primary Partition — up to four on one disk
- Extended Partition — serve as a place holder for logical partitions
- Logical Partition — reside within an extended partition
- The numbering scheme for primary partitions is 1 through 4 (does not need to be sequential)
- Logical partitions are numbered 5 and up (must be sequential)
- The first bit of code executed by the CPU will be from the first sector of the disk on an MBR system
- this makes the system vulnerable to damage, and accidents could render it useless
- Backups of the MBR are useful and encouraged
- Type codes are used to indicate which type of file system is loaded
- [ 0x0c ] — FAT
- [ 0x05 ] — an old type of extended partition
- [ 0x07 ] — NTFS
- [ 0x0f ] — a newer type of extended partition
- [ 0x82 ] — Linux Swap
- [ 0x83 ] — Linux File System
- The MBR structure is old and us not easily usable beyond a 2TiB disk
- GPT
- GUID Partition Table (GPT) uses a system which makes utilities think that it is an MBR system
- GPT is an EFI specification, but can be used on computers without EFI and UEFI
- GPT is usable beyond the 2TiB limitation of the MBR system
- GPT does not have the primary / extended / logical system that MBR uses. Up to 128 partitions can be defined and the numbering system used for identifying the partitions need not be sequential
- Supporting utilities for GPT management are not as prevalent as those for MBR
- LVM
- A alternate partitioning scheme to MBR or GPT is Logical Volume Management (LVM)
- LVM allows you to resize your logical volumes without worrying about the positions or sizes of surrounding partitions
- A serious drawback can be the difficulty of recovery if an LVM spans multiple disks
- LVM is useful for very large filesystems which are too large for a single physical disk