iostat / vmstat / mpstat are some tools to monitor server performance.
* iostat reports CPU, disk I/O, and NFS statistics.
* vmstat reports virtual memory statistics.
* mpstat reports processors statictics.
iostat
Iostat without any argument displays information about the CPU usage, and I/O statistics about all the partitions on the system are showing:
# iostat
Linux 2.6.18-164.el5 (cloudcc.ctechz.blogspot.com) 03/11/2012
avg-cpu: %user %nice %system %iowait %steal %idle
1.98 17.92 8.59 0.33 0.00 71.17
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 13.89 33.54 365.15 14323873 155932064
sda1 13.84 32.34 363.73 13808779 155327336
sda2 0.05 1.20 1.42 514566 604728
Display only cpu statistics
# iostat -c
Linux 2.6.18-164.el5 (cloudcc.ctechz.blogspot.com) 03/11/2012
avg-cpu: %user %nice %system %iowait %steal %idle
1.98 17.92 8.59 0.33 0.00 71.17
Display only disk I/O statistics
# iostat -d
Linux 2.6.18-164.el5 (cloudcc.ctechz.blogspot.com) 03/11/2012
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 13.89 33.53 365.04 14323921 155949184
sda1 13.84 32.32 363.62 13808827 155344456
sda2 0.05 1.20 1.42 514566 604728
Display only network statistics
-n, displays only the device and NFS statistics.
# iostat -n
Linux 2.6.18-164.el5 (cloudcc.ctechz.blogspot.com) 03/11/2012
avg-cpu: %user %nice %system %iowait %steal %idle
1.98 17.93 8.59 0.33 0.00 71.17
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 13.89 33.52 365.00 14323937 155957552
sda1 13.84 32.32 363.58 13808843 155352824
sda2 0.05 1.20 1.42 514566 604728
Device: rBlk_nor/s wBlk_nor/s rBlk_dir/s wBlk_dir/s rBlk_svr/s
wBlk_svr/s rops/s wops/s
192.168.1.4:/home/pac 90.67 0.00 0.00 0.00 5.33 0.00
192.168.1.4:/bkp 8.74 0.00 0.00 0.00 8.74 0.00
192.168.1.8:/media 0.02 0.00 0.00 0.00 0.01 0.00
Display I/O data in MB/second
By default iostat, displays the device I/O statistics in Blocks. To change it to MB, use -m as shown
# iostat -m
Linux 2.6.18-164.el5 (cloudcc.ctechz.blogspot.com) 03/11/2012
avg-cpu: %user %nice %system %iowait %steal %idle
1.98 17.93 8.59 0.33 0.00 71.16
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda 13.88 0.02 0.18 6994 76165
sda1 13.83 0.02 0.18 6742 75869
sda2 0.05 0.00 0.00 251 295
Display I/O statistics only for a device
# iostat -p sda
Display timestamp information
# iostat -t
Linux 2.6.18-164.el5 (cloudcc.ctechz.blogspot.com) 03/11/2012
Time: 05:51:24 PM
avg-cpu: %user %nice %system %iowait %steal %idle
1.98 17.93 8.59 0.33 0.00 71.16
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 13.88 33.49 364.77 14324049 156006600
sda1 13.83 32.29 363.35 13808955 155401872
sda2 0.05 1.20 1.41 514566 604728
Execute Every x seconds – y number of times
# iostat 2
# iostat 2 3 — execute every 2 seconds for 3 times
Display LVM statistic
# iostat -N
# vmstat
procs ———–memory—————– —swap– ——io—- —system– —–cpu–
r b swpd free buff cache si so bi bo in cs us sy id wa st
1 0 196112 75232 151884 611352 0 0 8 91 45 40 20 9 71 0 0
vmstat output contains the following fields:
Procs – r: Total number of processes waiting to run
Procs – b: Total number of busy processes
Memory – swpd: Used virtual memory
Memory – free: Free virtual memory
Memory – buff: Memory used as buffers
Memory – cache: Memory used as cache.
Swap – si: Memory swapped from disk (for every second)
Swap – so: Memory swapped to disk (for every second)
IO – bi: Blocks in. i.e blocks received from device (for every second)
IO – bo: Blocks out. i.e blocks sent to the device (for every second)
System – in: Interrupts per second
System – cs: Context switches
CPU – us, sy, id, wa, st: CPU user time, system time, idle time, wait time
Display active and inactive memory
# vmstat -a
procs ———–memory———- —swap– —–io—- –system– —–cpu——
r b swpd free inact active si so bi bo in cs us sy id wa st
1 0 196112 75236 224864 787620 0 0 8 91 45 41 20 9 71 0 0
Display number of forks since last boot
This displays all the fork system calls made by the system since the last boot.
# vmstat -f
500235 forks
Execute Every x seconds
# vmstat 2
# vmstat 2 5
Display slab info
# vmstat -m
Display statistics in a table format
# vmstat -s
Display disk statistics
# vmstat -d
Display statistics for a partition
# vmstat -p /dev/sda1
Display in MB
# vmstat -S m
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