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29 votes

How to measure req/sec by analyzing apache logs

This great article helped me a lot... I had created a set of prepered commands that I am ...
Wazime's user avatar
  • 471
22 votes

Measure total latency of SSH session

See the sshping utility: Example: # sshping --- Login: 1725 msec --- Minimum Latency: 4046 nsec --- Median Latency: 11026 nsec +/- 0 std dev --- ...
Uncle Spook's user avatar
21 votes

Why the discrepancy between Speedtest and Wget?

ISPs often prioritize traffic to so that they can brag how fast their connections are, while in reality, they don't provide that much bandwidth. They're perfectly aware that most users ...
bviktor's user avatar
  • 908
19 votes

sar: enable data collecting

On Ubuntu 16.04 I just ran into this same issue. After some grousing around I found I needed to enable the service by editing the file /etc/default/sysstat Change ENABLED="false" to true: # Should ...
Gregory Martin's user avatar
17 votes

Why the discrepancy between Speedtest and Wget?

In addition to the other reasons posted, TCP connections don't work well with large files when the bandwidth-delay product becomes large. Like on an otherwise fast connection to an island. See ...
Andrew Henle's user avatar
  • 1,282
15 votes

At what point is a server considered idle?

A machine is idle when it's not performing the task it's supposed to perform for lack of requests. For example, if you had an email server, you could determine if it was fielding any requests from the ...
Spooler's user avatar
  • 7,136
13 votes

What exactly do the colors in htop status bars mean?

There are several different colors for each of the bars, except the Swap bar. Here are the color keys used inside of htop:
Roel Van de Paar's user avatar
11 votes

sar: enable data collecting

The sysstat service and associated timers need to be started: systemctl start sysstat sysstat-collect.timer sysstat-summary.timer To auto-start on next system startup: systemctl enable sysstat ...
Tom Hale's user avatar
  • 1,165
10 votes

Measure total latency of SSH session

I skipped some steps suggested by @nicht-verstehen: python -m timeit --setup 'import subprocess; p = subprocess.Popen(["ssh", "user@host", "cat"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, ...
hzpc-joostk's user avatar
9 votes

How to compare mainframe CPU performance?

Kevin mentions a number of great points, but it might help to start the analysis at a little higher level: what are the two machines and, since we're talking about Tomcat which runs in a JVM, do both ...
randomScott's user avatar
9 votes

How to compare mainframe CPU performance?

Comparing the number of CPUs of a mainframe image isn't meaningful, most likely. Mainframes are designed to run multiple tasks at the same time, and give priority to whatever the business says is ...
Kevin McKenzie's user avatar
8 votes

Measure total latency of SSH session

Was trying to do this myself and came up with this. Probably there is a simpler way, but this is what I came up with. First, prepare pipes which will be used to make the benchmarking program ...
Nicht Verstehen's user avatar
8 votes

At what point is a server considered idle?

"Idle" is not a black and white concept: even a busy server can have free CPU cycles, IOPs and memory to run some other application. As a rule of thumb, target CPU load should be at around ~80% and ...
shodanshok's user avatar
  • 50.9k
7 votes

Why the discrepancy between Speedtest and Wget?

wget give good practical measure of the speed. The tests of Speedtest probably include kind of parallelism which can explain higher numbers. For good average speed test I think the time for download ...
Romeo Ninov's user avatar
  • 5,957
6 votes

Measure total latency of SSH session

My idea was to use terminal query sequences for this; the advantage is that this can simply be run on the server, the disadvantage is that it measures terminal latency, not only the latency of the ...
laanwj's user avatar
  • 161
6 votes

How to guarantee CPU time for VPS?

Typically you get what you pay for and relatively cheap hosting providers can only offer their services at a competitive price by overcommitting CPU several times i.e. on a server with 48 cores and ...
HBruijn's user avatar
  • 80.6k
5 votes

Does it make sense to use perfmon in a vSphere infrastructure?

Of course it would. Why wouldn't it? There's nothing saying you can't use both perfmon and vCenter counters to monitor the performance of your VMs - perfmon is better at or easier to set up for some ...
HopelessN00b's user avatar
5 votes

Windows / NTFS - is it possible to measure completion time of file operations?

Hire somebody to write either monolithic or mini filter driver for file system. You'll be able to intercept all calls from particular app of interest and track them right to NTFS or any other FS ...
BaronSamedi1958's user avatar
4 votes

Find out which task is generating a lot of context switches on linux

In newer kernel version sudo perf record -e context-switches -a # record the events # then ctrl+c sudo perf report # inspect the result This will give you the exactly result about context-...
snyh's user avatar
  • 141
4 votes

What exactly do the colors in htop status bars mean?

Anyone who just upgraded to Debian 12 (Bookworm), may have noticed a new colour in the RAM, purple. Purple represents "shared" memory.
Mint's user avatar
  • 516
4 votes

Configure Windows Server Performance Monitor to create new log for every day

To have onr file per day, you can do like this. On my server I store on file per day during 7 days. It deletes the oldest files. In the properties of yours performances counters : You can prefix the ...
Sorcha's user avatar
  • 1,335
4 votes

Why the discrepancy between Speedtest and Wget?

One reason could be that often the maximum speed cannot be reached by just a single TCP connection. recently introduced a single connection mode. Try this and see if it makes a ...
Josef's user avatar
  • 381
4 votes

ESXi (Free Versions) Notifications when there is sustained high CPU usage

There's no way to do this natively with the free version of ESXi, but you can use a third party program to do this for you. I use Veeam One Community Edition. It's free and it's a great product. ...
joeqwerty's user avatar
  • 111k
3 votes

Is there a way to monitor the state of the same process across different windows machines?

The way this is handled is with a monitoring tool that monitors the servers from a centralized location. Different monitoring tools work in different ways. Some of them use agents that must be ...
Ryan Ries's user avatar
  • 55.9k
3 votes

Optimal configuration of "Processor load is too high" trigger in Zabbix

I would suggest something like this: {Template OS Linux:system.cpu.load[percpu,avg15].avg(15m)}>1.8 The purpose being that you want a slower response time on your alarms rather than raising to a ...
Tel's user avatar
  • 31
3 votes

What is the closest equivalent of "load average" in Windows available via WMI?

If you're using Python, psutil emulates getloadavg() on Windows via the Processor Queue Length: >>> import psutil >>> psutil.getloadavg() (3.14, 3.89, 4.67) PR showing how this ...
Giampaolo Rodolà's user avatar
3 votes

Faster alternative to echo 3 > /proc/sys/vm/drop_caches

If you need to reset the system after a test run, why not quick reboot using kexec-reboot? This would probably reboot the server in 45-60 seconds, and is a much cleaner approach to what you're doing. ...
ewwhite's user avatar
  • 198k
3 votes

Windows Server Core network and disk resource monitoring

Remote perfmon is one way to go. As you cite both GUI and CLI based goals, I'm not sure which you're most intereted in. There are many WMI classes for performance counters (list with gwmi -list ...
Clayton's user avatar
  • 4,573
3 votes

Disk Queue length of 30 in Azure App Service, that can't be right

To me, that sounds high as well, with Azure your in a shared pool environment. I bet your back-end disk is getting hammered by other clients. Based on other posts it sounds like Azure is known for ...
SpiderIce's user avatar
  • 561

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