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--- linux_wiki:sar [2014/12/03 21:32]
billdozor
+++ linux_wiki:sar [2019/05/25 23:50] (current)
@@ Line 1: / Line 1: @@
 ====== sar (system activity report) ======
+**General Information**
 sar is used for displaying collected activity counters of various OS stats, including CPU, memory, swap, and disk I/O.
-sar is a command provided by the sysstat package.
+**Checklist**
+  * Distro(s): Any
+  * Package: sar is a command provided by the "sysstat" package.
+----
 ===== Installation and Configuration =====
@@ Line 25: / Line 32: @@
 Look for a line like this to edit:
+<code>
 # Activity reports every 10 minutes everyday
 -55/10 * * * * root command -v debian-sa1 > /dev/null && debian-sa1 1 1
+</code>
 ) Start the service
@@ Line 45: / Line 54: @@
 After sysstat has collected data for a while, you can start to view the information with sar.
-=== Log location ===
+==== Log location ====
 Sar logs to either:
   * /var/log/sysstat/
@@ Line 63: / Line 72: @@
 ----
-=== CPU Utilization ===
+==== CPU Utilization ====
-<code bash>
+<code>
 sar -u  (displays for current day until that point)
 sar -u 1 5  (display real time CPU every 1 second, 5 times)
@@ Line 90: / Line 99: @@
 ----
-=== Memory (RAM) Stats ===
+==== Memory (RAM) Stats ====
-<code bash>
+<code>
 sar -r  (display todays memory stats)
 sar -r 2 10  (display real time memory stats every 2 seconds, 10 times)
 </code>
+<code bash>
 sar -r
 Linux 3.13.0-39-generic (dt-bill) 	12/03/2014 	_x86_64_	(4 CPU)
@@ Line 101: / Line 111: @@
 :25:01 PM kbmemfree kbmemused  %memused kbbuffers  kbcached  kbcommit   %commit  kbactive   kbinact   kbdirty
 :35:01 PM   6514076   1661656     20.32     94056    657736   2300940     13.89   1008760    455492       580
+</code>
 Columns (probably the only ones you care about):
@@ Line 109: / Line 120: @@
 ----
-=== Swap Stats ===
+==== Swap Stats ====
+<code>
+sar -S  (todays swap usage)
+</code>
+<code bash>
+sar -S
+Linux 3.13.0-39-generic (dt-bill) 	12/03/2014 	_x86_64_	(4 CPU)
+:25:01 PM kbswpfree kbswpused  %swpused  kbswpcad   %swpcad
+:35:01 PM   8388604         0      0.00         0      0.00
+</code>
+Columns:
+  * kbswpfree => Free swap space in kilobytes
+  * kbswpused => Used swap space in kilobytes
+  * %swpused => % used swap space
+  * kbswpcad => Cached swap in kilobytes. This is memory that once was swapped out, is swapped back in but still also is in the swap area (if memory is needed it doesn't need to be swapped out again because it is already in the swap area. This saves disk I/O)
+    * **Explanation**: If the kernel needs more space in memory(RAM), it moves aging processes to slower disk swap space.(swap out of memory) If those processes are needed again, they are moved back to RAM (swapped in). The copies are NOT deleted from disk swap space; there is no need to waste disk I/O on doing this unless something else needs the disk swap space.
+----
+==== Disk I/O ====
+<code>
+sar -b  (todays disk I/O and transfer rates)
+</code>
+<code bash>
+sar -b
+Linux 3.13.0-39-generic (dt-bill) 	12/03/2014 	_x86_64_	(4 CPU)
+:25:01 PM       tps      rtps      wtps   bread/s   bwrtn/s
+:35:01 PM     26.47     23.27      3.20    765.51    464.86
+</code>
+Columns:
+  * tps => transfers per second (both disk reads and writes)
+  * rtps => read requests per second
+  * wtps => write requests per second
+  * bread/s => blocks read per second (block = sector = 512 bytes)
+  * bwrtn/s => blocks written per second (block = sector = 512 bytes)
+----
+==== Network Stats ====
+<code>
+sar -n TYPE (todays network statistics)
+</code>
+TYPE can be:
+  * DEV => devices vital stats (eth0, eth1, etc)
+  * EDEV => device failure stats
+  * NFS => NFS client activity
+  * NFSD => NFS server activity
+  * IP => IPv4 network traffic
+  * TCP => TCPv4 network traffic
+  * UDP => UDPv4 network traffic
+  * ALL => All of the above (and more). Warning: this will be very long.
+Example (device stats for just eth1 from 5pm to 6pm today)
+<code bash>
+sar -n DEV -s 17:00:00 -e 18:00:00 | grep eth1
+:25:01 PM     IFACE   rxpck/s   txpck/s    rxkB/s    txkB/s   rxcmp/s   txcmp/s  rxmcst/s   %ifutil
+:35:01 PM      eth1     13.77     11.45     12.31      1.37      0.00      0.00      0.05      0.01
+:45:01 PM      eth1     23.35     17.53     27.06      2.09      0.00      0.00      0.04      0.02
+:55:01 PM      eth1     50.00     35.92     63.80      3.92      0.00      0.00      0.04      0.05
+Average:         eth1     29.04     21.64     34.39      2.46      0.00      0.00      0.04      0.03
+</code>
+----
+==== Start and End ====
+Report only specfic time periods
+CPU stats for today, from 6pm to 6:30pm
+<code bash>
+sar -u -s 18:00:00 -e 18:30:00
+</code>
+Memory stats 1pm to 3pm, from the 1st day of the month
+<code bash>
+sar -r -s 13:00:00 -e 15:00:00 -f /var/log/sysstat/sa01
+</code>