Questions tagged [sar]
System Activity Report: a Unix/Linux command to display various system loads (Wikipedia).
67
questions
0
votes
0
answers
22
views
Two disks in mdadm but one has much higher aqu-sz, await, %util
I have two disks in an mdadm RAID1 array but (at times at least) they seem to be performing very differently from one another:
07:24:53 AM tps rkB/s wkB/s dkB/s areq-sz aqu-sz ...
- 31
0
votes
1
answer
202
views
what is the link between SAR memory output and free command?
I now understand a bit more RAM usage in linux OS and I knwo that I can use free -h to have correct knowledge about RAM utilization in my server.
but I also have SAR that is working on my server and I ...
- 25
0
votes
0
answers
85
views
rhel + disk util is very high , what is the impact for long term
we have backup server with rhel version 7.2
server is VM machine , and OS disk is VMDK disk
disk used space is around - 50% , and from smartctl we not see problem
as we can see from follwing details
...
- 697
0
votes
1
answer
280
views
High I/O wait and Context Switches - how to debug
Update:
sar -W -B -d output added to bottom of post.
I have simulated this on boot. I have uwsgi starting 9 instances of a django app, along with gunicorn for websockets, and dramatiq for queue ...
- 123
1
vote
1
answer
1k
views
sar high memory commit %
I've noticed that there's a high percentage of memory committed on this server during a specific timeframe. Although, memory usage still looks fine overall from sar output. I don't see 'out of memory' ...
- 21
0
votes
0
answers
161
views
enough memory for downscale ubuntu server?
Management decided to downscale prod server.
Current size: Standard B16ms (16 vcpus, 64 GiB memory)
Desired size: Standard B8ms (8 vcpus, 32 GiB memory)
CPU is mostly idle (output is from sar -u)...
- 115
6
votes
2
answers
3k
views
sar service has stopped collecting data
We had sar working on our Ubuntu server, but did some work on the server and now it's stopped logging to the day's logfile.
sar -b 5 5
This indicates that sar is alive, and monitoring data, but
...
- 163
0
votes
0
answers
555
views
High I/O wait in apache tomcat server
Facing high I/O wait in apache tomcat server when the load increases.
Suspecting disk I/O is less when tomcat is running however. disk IO seems drops drastically when tomcat is running along with the ...
1
vote
1
answer
959
views
How to write pidstat output to a sadc file for analysis later (sar)
How can I write the output of pidstat to a file for analysis later?
In sar, you can monitor usage and write-out to a file for later analysis using the -o argument. From the man page:
If ...
- 891
0
votes
1
answer
2k
views
sar and top show high cpu usage, but vmstat and ps show low cpu usage. Why?
I'm diagnosing a high CPU usage event, and I found a weird difference between numbers from ps/vmstat, which show almost 0%, and sar/top, which show almost 100% (user + system):
sar 1 5
Linux 2.6.9-67....
0
votes
1
answer
2k
views
Stop sysstat sar
How to stop sar collecting system activity without uninstalling sysstat? I have used systemctl stop sysstat but as I understand from running sar it continues collecting system activity.
1
vote
1
answer
168
views
Control-C sends control-alt-delete to my Ubuntu server over ssh
On my Ubuntu VM:
Linux xxxxxxx 3.19.0-25-generic #26~14.04.1-Ubuntu SMP Fri Jul 24
21:16:20 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
to which I am connected over SSH, I am running this command:
sar ...
- 11
1
vote
1
answer
2k
views
sar + get network info from sar
this syntax give the network info on sa1 file
sar -n DEV -f /var/log/sa/sa1
how to get the info only from UDP protocol ?
we try also
sar -n UDP -f /var/log/sa/sa1
Requested activities not ...
- 511
0
votes
0
answers
1k
views
sar -dp reports individual disks higher than their devicemapper logical volume
I am trying to figure out how sysstat is reporting the utilization of the device mapper logical volume, lower than the individual disks that make up the logical volume. I keep trying to do the math ...
- 46
1
vote
1
answer
522
views
Update sa reports every 6 hours
On SuSE Linux the default cron-job for sa/sar looks like this:
# /etc/cron.d/sysstat
# Activity reports every 10 minutes everyday
*/10 * * * * root [ -x /usr/lib64/sa/sa1 ] && exec /usr/lib64/...
- 3,963
0
votes
0
answers
101
views
reducing tps in kafka disks on linux
we're using kafka brokers with:
24 HT cores
256GB RAM
16 X 7.2K RPM NLSAS disks configured in RAID-10 and replication
factor 3.
the sar -q
command the runq-sz reached ~40 on average, load average ...
- 61
-1
votes
1
answer
846
views
After installing sysstat on an AWS EC2 instance: kernel: ena: Feature 27 isn't supported
After installing and enabling sysstat on an AWS EC2 instance I get the following log entries everytime sysstat is run (from the cronjob in /etc/cron.d/sysstat) in my /var/log/syslog file on Debian:
...
- 6,519
1
vote
2
answers
4k
views
How does sar collect/calculate disk utilization %?
I'm pretty sure sar's disk utilization % shows how much of the disk is being utilized at any given time, but how does it calculate that? I found:
%util
Percentage of CPU time during which I/O ...
- 429
0
votes
1
answer
1k
views
How is rxkB/s and wxkB/s calculated in SAR -n DEV command?
sar -n DEV 1 1 command
gives the stats rxkB/s(Number of kilobytes read from the device per second.) and wxkB/s (Number of kilobytes written to the device per second.)
Is it possible to calculate ...
- 101
22
votes
4
answers
28k
views
sar: enable data collecting
I've just installed the sysstat package on Manjaro. When running sar for the first time I see:
Cannot open /var/log/sa/sa21: No such file or directory
Please check if data collecting is enabled
How ...
- 1,185
1
vote
1
answer
213
views
Take all sadc (sar) data from production, and analyze it on another machine
sadc is running on the production server.
When a incident happens, I want the admin to give me all the data (going back in the past as far as possible) so that I can analyze the incident and also ...
- 1,394
1
vote
2
answers
1k
views
How to view historical usage metrics, per process?
My first inclination here would be something built into SAR, or the sysstat package in general. If that is indeed the case however, I can't seem to find this solution.
What I would like to see, and ...
- 895
0
votes
1
answer
2k
views
How to find network latency for network interfaces using SAR on linux environment
I want to get the network latency for network interfaces using SAR on linux environment.
sar -n command provides following output:
10:00:13 AM IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s ...
- 3
1
vote
2
answers
2k
views
What's the caculation for network speed reported with sar-n DEV output?
I am confused about the network speed outputs:
If the report says:
sar -n DEV 1 1
Linux 2.6.18-194.el5PAE (dev-db) 03/26/2011 _i686_ (8 CPU)
01:11:13 PM IFACE rxpck/s txpck/s ...
- 771
0
votes
1
answer
376
views
sar-like Utility For File Access
I'm troubleshooting a linux server's performance degradation from last night. I have sysstat installed on the server and it's polling every 2 minutes. At around the time the event happened, there ...
- 479
0
votes
0
answers
464
views
runqueue length in vmstat and sar
i am looking at the vmstat output to assess certain performance degradation on our systems, specifically for long runqueue. i find frequently it looks like this on a 8 CPU m/c:
Mon Jun 13 12:14:02 ...
- 1
1
vote
1
answer
543
views
What is the best way to analyze data captured from sar?
I've got some sysstat data that has been captured from servers with SAR, and I'm unsure what is the best way to analyze that data.
I've found ksar, but it seems to be quite old and out of date. I'd ...
- 135
1
vote
0
answers
360
views
Does an NFS client incur read/write page faults proportional to bytes read to/written from server?
Perhaps my knowledge of virtual memory has been supplanted by too much other junk.
Recently I ran some database benchmark tests where all data was to be stored on an NFS server and accessed via NFSv3 ...
- 81
6
votes
1
answer
34k
views
How to find what processes were running at a time in the past?
I am asked to investigate a high CPU usage alert which occurred this morning. I used sar -p and saw the high CPU usage showing up at that time
Next I used ps -eo pcpu,pid,user,args | sort -r -k1 | ...
- 163
2
votes
1
answer
311
views
HP UX iostat on File System
I have a server running HP UX 11 OS and I'm trying to have I/O statistics for File System and not disk.
For example, I have 50 disk attached to the server when I type iostat (here under output of ...
- 21
0
votes
2
answers
777
views
Shell Script to check CPU Utilisation
I am trying to write a shell script which will check free memory of the server.
I am trying below code
top -M -n1 | grep "Mem" | awk '{print 0 + $7}' | awk '{ print $1 / 1024 }' | awk '{if ($1 < ...
- 1
1
vote
0
answers
840
views
how to filter sar -d disk output tidily
sar -D output-I would like a suitable command to run alongside stress -hdd but this is the output which sar -D 1 10 gives. I have filtered it using both awk |'NR > 1 {printf "%4s%8s%8s\n",$13,$14,$...
- 11
0
votes
0
answers
1k
views
Why top output different from sar output?
This is SLES11sp3 system.
The command top shows the load average of 17+, as shown below:
#top
top - 11:59:14 up 19 days, 21:55, 40 users, load average: 17.09, 17.29, 19.22
Tasks: 514 total, 1 ...
- 189
0
votes
1
answer
2k
views
interpreting disk stats using sar
I have JBOD and Cassandra installed on it. I'm trying to figure out if my disk are totally free or they are boring. The sar -d result is in the end. As I understand until %util is low (less then 1) it ...
- 103
1
vote
0
answers
166
views
What is the difference between sar -B verses sar -W
I am trying to understand why my system is running slowly. I found the sar command, but wanted to know the difference between sar -B and sar -W
I read the man page, and I understand that -B gives me ...
- 119
1
vote
1
answer
201
views
High load on a particular time
I am facing one odd problem in one of my remote servers (Centos 6). Its load became high by 09:30 AM and became normal by 09:40. See my SAR -q on 2 days.
09:00:01 PM 4 199 0.95 ...
- 109
0
votes
0
answers
270
views
Nor able to parse the SAR output
We are using SuSE 10 OS and lately I wish to know the total network bandwidth used for a period of time lets say for 1 week.
We have sar enabled and the sar data for a week is there.
Now I know how ...
5
votes
3
answers
5k
views
How to Change sysstat/sar logging folder
I have just enabled sysstat on one of my servers (Ubuntu 12.04), I have noticed it is logging all to
/var/log/sysstat/sa04
/var/log/sysstat/sa05
/var/log/sysstat/sar04
How can I change the sysstat ...
- 1,241
3
votes
1
answer
7k
views
opening sar activity files error "Invalid system activity file"
Note: I opened this question on Stackoverflow first and realized that this is the right place for the question. Just stating that it is not a duplicate, already closed the question on SO.
I am new ...
- 135
2
votes
1
answer
4k
views
report per-process IO stats with pidstat or sar
I'm trying to track io usage of a few "suspect" processes over time. Ideally would like to make those stats available via munin, or push directly to graphite. However, as a starting point it would be ...
- 601
0
votes
1
answer
397
views
High CPU usage in RHEL machine
I have RHEL machine that runs postgres-9.1 database.
In a particular time, sar output shows as follows:
Refer link for snapshot: http://imgur.com/gKcOhOX,vNwTpwC#0
where as %user is high between 12:...
4
votes
0
answers
2k
views
Why are pgpgin/s and majflt/s inconsistent in sar -B?
In sar -B ouptut, I would naively expect pgpgin/s to equal majflt/s multiplied by the system page size. From man sar:
pgpgin/s
Total number of kilobytes the system paged in ...
- 141
13
votes
3
answers
32k
views
Relation between disk IOPS and sar tps
I'm trying to estimate IOPS requirements of my application running on 32-bit CentOS 6.2. I started to take some measurement on a machine with SATA disks and I'm quite confused of difference between ...
- 375
3
votes
2
answers
1k
views
Reporting historical system activity in FreeBSD
I'd like to record data about system activity under FreeBSD for future analysis. If I were running a SysV system, I'd just sar and its related utilities, but that doesn't exist in the BSDs. (And ...
- 6,978
-1
votes
2
answers
506
views
How to find DEVICE on which read per second (rd_sec/s) is highest?
I am using awk to find out DEVICE on which read per second (rd_sec/s) is highest, (from SAR file) below is my command :
# sar -d -f sa28 | awk '{print $3,$4}' |sort -k1,1n
Output is showing on ...
- 51
1
vote
1
answer
378
views
How to track down sudden increase in process numbers (linux)
I find it pretty common for a Linux server to slow down to the point of complete unresponsiveness (LA 150+ etc), which when looking at it later using sar or munin or whatever it will show a sudden ...
- 356
3
votes
3
answers
24k
views
High await in sar
My database server has the following sar output for the data device:
[postgres@dbsrv07 ~]$ LC_ALL=POSIX sar -d |egrep "await|dev253-2"
00:00:01 DEV tps rd_sec/s wr_sec/s avgrq-sz ...
- 151
7
votes
3
answers
15k
views
Invalid system activity (sysstat) file on Ubuntu server
I'm periodically getting this message from the daily cron on my server. (I don't get this message every day.)
/etc/cron.daily/sysstat:
Invalid system activity file: /var/log/sysstat//sa28
Here's ...
- 711
3
votes
1
answer
9k
views
Sar: Free memory statistics (including buffers, cache)
The free commands gives the amount of free memory in two forms: completely free memory (the Mem line) and disposable memory used for caches and buffers (the -/+ buffers/cache line):
-bash-3.2$ free -...
- 13.8k
1
vote
2
answers
5k
views
Linux SAR/SAT Daily Reports to store more than a month?
I'm on RHEL. How can i extend the log interval of SAR Reports to be more then a month? Normally the daily SAR reports are something like:
[root@server /]# cat /var/log/sa/sa
sa01 sa21 sa23 ...
- 475