RB12- System Performance
Terms
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- what are the 3 types of work loads?
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1. workstation
2. multiuser
3. server - nice and renice.
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The nice and renice commands are used to change the priority of a process.
The nice command runs another command at a different priority, while the
renice command changes the priority of an already running process. - schedtune
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The schedtune command allows you to modify the default behavior of the
scheduling system for threads and processes, and should be used with extreme
care by experienced administrators. - svmon
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Captures and analyzes a snapshot of virtual memory.
time Prints the elapsed execution time and the user and system
processing time attributed to a command.
- lslv
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Displays information about a logical volume or the logical volume
allocations of a physical volume.
- tprof
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Reports CPU usage for individual programs and the whole system.
- reorgvg
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Reorganizes the physical-partition allocation within a volume group.
- ps
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Displays the status of processes.
- what does the vmstat command do?
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The vmstat command reports statistics about kernel threads, virtual memory,
disks, traps, and CPU activity. - sar
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The sar command writes to standard output the contents of selected cumulative
activity counters in the operating system. - renice
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Changes the priority of one or more processes.
- nice
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Runs a command at higher- or lower-than-normal priority.
no Displays or sets network options.
- memory bound?
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A system is memory-bound if some virtual memory is forced
out to disk, meaning the system is waiting on a relatively slow
disk instead of relatively fast RAM. This is indicated by a
non-zero value in the page-in (pi) and page-out (po) values. - lsattr
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Displays the attributes of devices.
- iostat
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Reports CPU and I/O statistics.
- nfsstat
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Displays statistics about Network File System (NFS) and Remote
Procedure Call (RPC) activity.
- what is the svmon command used for?
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The svmon command provides a more in-depth analysis of memory usage. It is
more informative, but also more intrusive, than the vmstat commands. - netstat
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Displays the contents of network-related data structures.
- what is the netstat command used for?
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The netstat command symbolically displays the contents of various
network-related data structures for active connections. - how is the iostat command used?
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The iostat command is used for monitoring system input/output device loading
by observing the time the physical disks are active in relation to their average
transfer rates. - trace
- Records and reports selected system events.
- vmstat
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Reports virtual-memory activity and other system statistics.
- what is the wlm?
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The Workload Manager (WLM) allows the system administrator to divide
resources between jobs. - cpu bound?
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A system is said to be CPU-bound if the total system (sy) and
user (us) CPU usage is approaching 100 percent. This would
imply that idle time and wait time for CPU are approaching
zero. - what 2 reports does the iostat command generate?
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The iostat command generates two types of reports, the tty and CPU Utilization
report and the Disk Utilization report.