free -h #사람이 보기 편한 단위

RAM unused

• Free memory: Simply memory that is not currently being used for any tasks.
• Available memory: Memory that is actually available for use by a new application or process, including memory that is currently being used as a buffer/cache but can be returned when needed.

Buffer

• A buffer is a memory area that temporarily stores data before writing it to disk.
• Mainly used to improve the performance of disk write operations.
• For example, instead of writing data directly to disk, it is first stored in a buffer, and then written to disk all at once when the buffer is full or certain conditions are met. This allows disk I/O to be handled efficiently.

Cache

• Cache is an area where data read from disk is stored in memory so that it can be quickly accessed later.
• Mainly used to improve the performance of disk read operations.
• By storing frequently used data or program files in the cache, you save time accessing the disk again.

Meaning of buff/cache

• buff/cache represents the total amount of memory being used as buffers and cache.
• The system is using this memory, but it can be reused as memory requested by the application when needed.
• Therefore, when calculating the actual available memory, buff/cache can be considered free memory.