What is vmstat output?
Resolution. vmstat (virtual memory statistics) is a valuable monitoring utility, which also provides information about block IO and CPU activity in addition to memory.
What information can vmstat provide?
vmstat command in Linux/Unix is a performance monitoring command of the system as it gives the information about processes, memory, paging, block IO, disk, and CPU scheduling.
What is the difference between vmstat and iostat?
vmstat command (also known as virtual memory statistic tool) shows information about processes, memory, disk, and CPU activity in Linux, whereas the iostat command is used to monitor CPU utilization, system input/output statistics for all the disks and partitions.
What does vmstat mean in Linux?
Virtual memory statistics reporter
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.
Why is vmstat useful?
The vmstat (virtual memory statistics) command allows you to monitor your system’s memory usage. It shows how much virtual memory there is, and how much is free and paging activity. You can observe page-ins and page-outs as they happen.
What is WA in vmstat?
The vmstat wa column is the percentage of time that the CPU was idle with pending local disk I/O and NFS-mounted disks. If there is at least one outstanding I/O to a disk when wait is running, the time is classified as waiting for I/O.
How do I check the size of a virtual machine in Linux?
Which linux command can I check the full size of the VM?
- lsblk or df -h.
- df which stands for “disk free” shows available memory space: try df -ah.
- lsblk, in which line can you see, whether you have extra 40 size in your virtual machine or not, or with df -h.
What is the use of vmstat in tuning?
Use vmstat to determine real and logical resource utilization. It samples kernel tables and counters and then normalizes the results and presents them in an appropriate format. By default, vmstat sends its report to standard out, but it can be run with the output redirected.
How do I read vmstat?
The vmstat command (short for virtual memory statistics) is a built-in monitoring utility in Linux. The command is used to obtain information about memory, system processes, paging, interrupts, block I/O, disk, and CPU scheduling. Users can observe system activity virtually in real-time by specifying a sampling period.
What is SWPD in vmstat?
According to the man page of vmstat , ‘swpd’ means the amount of virtual memory used. As my understanding, for most cases it should be zero unless the physical CPU is out of space.
What is %WA top?
%wa – this is iowait percentage. When a process or program requests some data, it first checks the processor caches (there are 2 or three caches there), then goes out and checks memory, and finally will hit disk.
How do I know the size of my VM?
The second approach to check VM sizes is using PowerShell. We can execute the cmdlet Get-AZVMSize -Location and a list containing all available VM sizes, including vCPUs, memory, data disk, OS disk size in MB, and resource disk size in MB will be listed.
How do I know the size of my virtual machine?
To get the specific Azure VM size, we need to first retrieve the VM details and then need to run the JMESPATH query to retrieve the VM size. you can also retrieve the size of the VM without resource group name, using “az vm list” command.
What is compaction OS?
Compaction is a technique to collect all the free memory present in form of fragments into one large chunk of free memory, which can be used to run other processes.
What is IO in disk?
Disk I/O includes read or write or input/output operations (defined in KB/s) involving a physical disk. In simple words, it is the speed with which the data transfer takes place between the hard disk drive and RAM, or basically it measures active disk I/O time.