1Z0-460 · Question #3
The DBA tells you that the system is not overloaded but you can tell that the system us actively swapping. What command would you run to show this information to the DBA?
The correct answer is B. # iostat 5 10. iostat - Report Central Processing Unit (CPU) statistics and input/output statistics for devices, partitions and network filesystems (NFS). The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to…
Question
The DBA tells you that the system is not overloaded but you can tell that the system us actively swapping. What command would you run to show this information to the DBA?
Options
- A
iotop
- B
iostat 5 10
- C
cat /proc/meminfo
- D
vmstat 5 10
How the community answered
(25 responses)- A4% (1)
- B84% (21)
- C8% (2)
- D4% (1)
Explanation
*iostat - Report Central Processing Unit (CPU) statistics and input/output statistics for devices, partitions and network filesystems (NFS). *The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to their average transfer rates. The iostat command generates reports that can be used to change system configuration to better balance the input/output load between physical disks. Not A: Related to kernel and processes. *iotop - simple top-like I/O monitor *iotop watches I/O usage information output by the Linux kernel (requires 2.6.20 or later) and displays a table of current I/O usage by processes or threads on the system. *iotop displays columns for the I/O bandwidth read and written by each process/thread during the sampling period. It also displays the percentage of time the thread/process spent while swapping in and while waiting on I/O. For each process, its I/O priority (class/level) is shown. In addition, the total I/O bandwidth read and written during the sampling period is displayed at the top of the Not C: related to RAM usage. *The entries in the /proc/meminfo can help explain what's going on with your memory usage, if you know how to read it. *High-Level Statistics MemTotal: Total usable ram (i.e. physical ram minus a few reserved bits and the kernel binary MemFree: Is sum of LowFree+HighFree (overall stat) MemShared: 0; is here for compat reasons but always zero. Buffers: Memory in buffer cache. mostly useless as metric nowadays Cached: Memory in the pagecache (diskcache) minus SwapCache SwapCache: Memory that once was swapped out, is swapped back in but still also is in the swapfile (if memory is needed it doesn't need to be swapped out AGAIN because it is already in the swapfile. This saves I/O) Not D:vmstat - Report virtual memory statistics
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