What is buff in vmstat?
buff: the amount of memory used as buffers. cache: the amount of memory used as cache. inact: the amount of inactive memory. (-a option) active: the amount of active memory. (-a option) Swap si: Amount of memory swapped in from disk (/s).
What is the vmstat command in Linux?
Virtual memory statistics reporter, also known as vmstat , is a Linux command-line tool that reports various bits of system information. Things like memory, paging, processes, IO, CPU, and disk scheduling are all included in the array of information provided. Subsequent reports use measurements of delay and count.
What is crontab used for in Linux?
Crontab stands for “cron table”. It allows to use job scheduler, which is known as cron to execute tasks. Crontab is also the name of the program, which is used to edit that schedule. It is driven by a crontab file, a config file that indicates shell commands to run periodically for the specific schedule.
What is the output of The vmstat command?
Basic vmstat Output 1 swpd – Total virtual memory. The swap space is initially unoccupied. However, the kernel starts using swap space as the… 2 free – Total free memory. 3 buff – Total memory temporarily used as a data buffer. 4 cache – Total cache memory. More
What are the active and inactive columns in vmstat?
If you use the -a (active) option the buff and cache memory columns are replaced by the “inact” and “active” columns. As they would suggest, these show the amount of inactive and active memory. To see these two columns instead of the buff and cache columns, include the -a option, as shown:
How are memory and swap statistics shown in vmstat?
The memory and swap statistics are now shown in megabytes. Note that the -S option does not affect the IO block statistics. These are always displayed in blocks. If you use the -a (active) option the buff and cache memory columns are replaced by the “inact” and “active” columns.
What should the delay value be in vmstat?
If you need to have rapid updates to try to diagnose a problem, it is recommended that you use a count value as well as a delay value. The count value tells vmstat how many updates to perform before it exits and returns you to the command prompt. If you do not provide a count value, vmstat will run until it is stopped by Ctrl+C.