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Managing System Information, Processes, and Performance in Oracle® Solaris 11.4

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Updated: August 2018
 
 

Monitor System Activities Using sar Command

    You can use the sar command to perform the following tasks:

  • Organize and view data about system activity.

  • Access system activity data on a special request basis.

  • Generate automatic reports to measure and monitor system performance as well as special request reports to pinpoint specific performance problems. For information about how to set up the sar command to run on your system as well as a description of these tools, see Collecting System Activity Data Automatically.

For a detailed description of this command, see the sar(1) man page.

Checking File Access

You can display file access operation statistics with the sar -a command.

$ sar -a
SunOS t2k-brm-24 5.10 Generic_144500-10 sun4v    ...
00:00:00  iget/s namei/s dirbk/s
01:00:00       0       3       0
02:00:00       0       3       0
03:00:00       0       3       0
04:00:00       0       3       0
05:00:00       0       3       0
06:00:00       0       3       0
07:00:00       0       3       0
08:00:00       0       3       0
08:20:01       0       3       0
08:40:00       0       3       0
09:00:00       0       3       0
09:20:01       0      10       0
09:40:01       0       1       0
10:00:02       0       5       0

Average        0       4       0

The operating system routines that are reported by the sar -a command are as follows:

iget/s

The number of requests made for inodes that were not in the directory name look-up cache (DNLC).

namei/s

The number of file system path searches per second. If namei does not find a directory name in the DNLC, it calls iget to get the inode for either a file or directory. Hence, most igets are the result of DNLC misses.

dirbk/s

The number of directory block reads issued per second.

The larger the reported values for these operating system routines, the more time the kernel is spending to access user files. The amount of time reflects how heavily programs and applications are using the file systems. The –a option is helpful to view whether an application is disk-dependent.

Checking Buffer Activity

You can display buffer activity statistics with the sar -b command.

The buffer is used to cache metadata. Metadata includes inodes, cylinder group blocks, and indirect blocks.

$ sar -b
00:00:00 bread/s lread/s %rcache bwrit/s lwrit/s %wcache pread/s pwrit/s
01:00:00       0       0     100       0       0      55       0       0

The following table describes the buffer activities that are displayed by the –b option.

Field Name
Description
bread/s
Average number of reads per second that are submitted to the buffer cache from the disk
lread/s
Average number of logical reads per second from the buffer cache
%rcache
Fraction of logical reads that are found in the buffer cache (100 % minus the ratio of bread/s to lread/s)
bwrit/s
Average number of physical blocks (512 bytes) that are written from the buffer cache to disk per second
lwrit/s
Average number of logical writes to the buffer cache per second
%wcache
Fraction of logical writes that are found in the buffer cache (100 % minus the ratio of bwrit/s to lwrit/s)
pread/s
Average number of physical reads per second that use character device interfaces
pwrit/s
Average number of physical write requests per second that use character device interfaces

The most important entries are the cache hit ratios %rcache and %wcache. These entries measure the effectiveness of system buffering. If %rcache falls below 90 percent or if %wcache falls below 65 percent, you might be able to improve performance by increasing the buffer space.

Example 20  Checking Buffer Activity

The following example of sar -b command output shows that the %rcache and %wcache buffers are not causing any slowdowns. All the data is within acceptable limits.

$ sar -b
SunOS t2k-brm-24 5.10 Generic_144500-10 sun4v    ...
00:00:04 bread/s lread/s %rcache bwrit/s lwrit/s %wcache pread/s pwrit/s
01:00:00       0       0     100       0       0      94       0       0
02:00:01       0       0     100       0       0      94       0       0
03:00:00       0       0     100       0       0      92       0       0
04:00:00       0       1     100       0       1      94       0       0
05:00:00       0       0     100       0       0      93       0       0
06:00:00       0       0     100       0       0      93       0       0
07:00:00       0       0     100       0       0      93       0       0
08:00:00       0       0     100       0       0      93       0       0
08:20:00       0       1     100       0       1      94       0       0
08:40:01       0       1     100       0       1      93       0       0
09:00:00       0       1     100       0       1      93       0       0
09:20:00       0       1     100       0       1      93       0       0
09:40:00       0       2     100       0       1      89       0       0
10:00:00       0       9     100       0       5      92       0       0
10:20:00       0       0     100       0       0      68       0       0
10:40:00       0       1      98       0       1      70       0       0
11:00:00       0       1     100       0       1      75       0       0

Average        0       1     100       0       1      91       0       0

Checking System Call Statistics

You can display system call statistics by using the sar -c command.

$ sar -c
00:00:00 scall/s sread/s swrit/s  fork/s  exec/s rchar/s wchar/s
01:00:00      38       2       2    0.00    0.00     149     120

The following list describes the system call categories that are reported by the –c option. Typically, reads and writes account for about half of the total system calls. However, the percentage varies greatly with the activities that are being performed by the system.

scall/s

The number of all types of system calls per second, which is generally about 30 per second on a system with four to six users.

sread/s

The number of read system calls per second.

swrit/s

The number of write system calls per second.

fork/s

The number of fork system calls per second, which is about 0.5 per second on a system with four to six users. This number increases if shell scripts are running.

exec/s

The number of exec system calls per second. If exec/s divided by fork/s is greater than 3, look for inefficient PATH variables.

rchar/s

The number of characters (bytes) transferred by read system calls per second.

wchar/s

The number of characters (bytes) transferred by write system calls per second.

Example 21  Checking System Call Statistics

The following example shows output from the sar -c command.

$ sar -c
SunOS balmy 5.10 Generic_144500-10 sun4v ...
00:00:04 scall/s sread/s swrit/s  fork/s  exec/s rchar/s wchar/s
01:00:00      89      14       9    0.01    0.00    2906    2394
02:00:01      89      14       9    0.01    0.00    2905    2393
03:00:00      89      14       9    0.01    0.00    2908    2393
04:00:00      90      14       9    0.01    0.00    2912    2393
05:00:00      89      14       9    0.01    0.00    2905    2393
06:00:00      89      14       9    0.01    0.00    2905    2393
07:00:00      89      14       9    0.01    0.00    2905    2393
08:00:00      89      14       9    0.01    0.00    2906    2393
08:20:00      90      14       9    0.01    0.01    2914    2395
08:40:01      90      14       9    0.01    0.00    2914    2396
09:00:00      90      14       9    0.01    0.01    2915    2396
09:20:00      90      14       9    0.01    0.01    2915    2396
09:40:00     880     207     156    0.08    0.08   26671    9290
10:00:00    2020     530     322    0.14    0.13   57675   36393
10:20:00     853     129      75    0.02    0.01   10500    8594
10:40:00    2061     524     450    0.08    0.08  579217  567072
11:00:00    1658     404     350    0.07    0.06 1152916 1144203

Average      302      66      49    0.02    0.01   57842   55544

Checking Disk Activity

You can display disk activity statistics with the sar -d command.

$ sar -d
00:00:00   device        %busy   avque   r+w/s  blks/s  avwait  avserv
device

Name of the disk device that is being monitored.

%busy

Portion of time the device was busy servicing a transfer request.

avque

Average number of requests during the time the device was busy servicing a transfer request.

r+w/s

Number of read-and-write transfers to the device, per second.

blks/s

Number of 512-byte blocks that are transferred to the device, per second.

avwait

Average time, in milliseconds, that transfer requests wait in the queue. This time is measured only when the queue is occupied.

avserv

Average time, in milliseconds, for a transfer request to be completed by the device. For disks, this value includes seek times, rotational latency times, and data transfer times.

Example 22  Checking Disk Activity

The following example illustrates the output from the sar -d command.

$ sar -d
SunOS balmy 5.10 Generic_144500-10 sun4v    ...
12:36:32   device        %busy   avque   r+w/s  blks/s  avwait  avserv

12:40:01   dad1             15     0.7      26     399    18.1    10.0
           dad1,a           15     0.7      26     398    18.1    10.0
           dad1,b            0     0.0       0       1     1.0     3.0
           dad1,c            0     0.0       0       0     0.0     0.0
           dad1,h            0     0.0       0       0     0.0     6.0
           fd0               0     0.0       0       0     0.0     0.0
           nfs1              0     0.0       0       0     0.0     0.0
           nfs2              1     0.0       1      12     0.0    13.2
           nfs3              0     0.0       0       2     0.0     1.9
           nfs4              0     0.0       0       0     0.0     7.0
           nfs5              0     0.0       0       0     0.0    57.1
           nfs6              1     0.0       6     125     4.3     3.2
           nfs7              0     0.0       0       0     0.0     6.0
           sd1               0     0.0       0       0     0.0     5.4
           ohci0,bu          0     0.0       0       0     0.0     0.0
           ohci0,ct          0     0.0       0       0     0.0     0.0
           ohci0,in          0     0.0       7       0     0.0     0.0
           ohci0,is          0     0.0       0       0     0.0     0.0
           ohci0,to          0     0.0       7       0     0.0     0.0

Note that queue lengths and wait times are measured when something is in the queue. If %busy is small, large queues and service times probably represent the periodic efforts by the system to ensure that altered blocks are promptly written to the disk.

Checking Page-Out and Memory

You can use the sar -g command to display page-out and memory freeing activities in averages.

$ sar -g
00:00:00  pgout/s ppgout/s pgfree/s pgscan/s %ufs_ipf
01:00:00     0.00     0.00     0.00     0.00     0.00

The output displayed by the sar -g command is a good indicator of whether more memory might be needed. Use the ps -elf command to show the number of cycles that are used by the page daemon. A high number of cycles, combined with high values for the pgfree/s and pgscan/s fields, indicates a memory shortage.

The sar -g command also shows whether inodes are being recycled too quickly and causing a loss of reusable pages.

The output from the –g option is as follows:

pgout/s

The number of page-out requests per second.

ppgout/s

The actual number of pages that are paged-out per second. A single page-out request might involve paging-out multiple pages.

pgfree/s

The number of pages per second that are placed on the free list.

pgscan/s

The number of pages per second that are scanned by the page daemon. If this value is high, the page daemon is spending a lot of time checking for free memory. This situation implies that more memory is needed.

%ufs_ipf

The percentage of ufs inodes taken off the free list by iget that had reusable pages associated with them. These pages are flushed and cannot be reclaimed by processes. Thus, this field represents the percentage of igets with page flushes. A high value indicates that the free list of inodes is page-bound, and that the number of ufs inodes need to be increased.

Example 23  Checking Page-Out and Memory

The following example shows output from the sar -g command.

$ sar -g
SunOS balmy 5.10 Generic_144500-10 sun4v    ...
00:00:00  pgout/s ppgout/s pgfree/s pgscan/s %ufs_ipf
01:00:00     0.00     0.00     0.00     0.00     0.00
02:00:00     0.01     0.01     0.01     0.00     0.00
03:00:00     0.00     0.00     0.00     0.00     0.00
04:00:00     0.00     0.00     0.00     0.00     0.00
05:00:00     0.00     0.00     0.00     0.00     0.00
06:00:00     0.00     0.00     0.00     0.00     0.00
07:00:00     0.00     0.00     0.00     0.00     0.00
08:00:00     0.00     0.00     0.00     0.00     0.00
08:20:01     0.00     0.00     0.00     0.00     0.00
08:40:00     0.00     0.00     0.00     0.00     0.00
09:00:00     0.00     0.00     0.00     0.00     0.00
09:20:01     0.05     0.52     1.62    10.16     0.00
09:40:01     0.03     0.44     1.47     4.77     0.00
10:00:02     0.13     2.00     4.38    12.28     0.00
10:20:03     0.37     4.68    12.26    33.80     0.00

Average      0.02     0.25     0.64     1.97     0.00

Checking Kernel Memory Allocation

The Kernel Memory Allocation (KMA) allows a kernel subsystem to allocate and free memory as needed.

    Rather than statically allocating the maximum amount of memory that might be needed under peak load, the KMA divides requests for memory into three categories:

  • Small (less than 256 bytes)

  • Large (512 bytes to 4 Kbytes)

  • Oversized (greater than 4 Kbytes)

The KMA keeps two pools of memory to satisfy small requests and large requests. The oversized requests are satisfied by allocating memory from the system page allocator.

The sar -k command is useful if you are checking a system that is being used to write drivers or STREAMS that use KMA resources. Any driver or module that uses KMA resources but does not specifically return the resources before it exits, can create a memory leak. A memory leak causes the amount of memory that is allocated by KMA to increase over time. Thus, if the alloc fields of the sar -k command increase steadily over time, there might be a memory leak. Another indication of a memory leak is failed requests. If this problem occurs, a memory leak has probably caused KMA to be unable to reserve and allocate memory.

If it appears that a memory leak has occurred, you should check any drivers or STREAMS that might have requested memory from KMA and not returned it.

You can use the sar -k command to report on activities of the Kernel Memory Allocator (KMA).

$ sar -k
00:00:00 sml_mem   alloc  fail  lg_mem   alloc   fail  ovsz_alloc  fail
01:00:00 2523136 1866512     0 18939904 14762364    0      360448     0
02:00:02 2523136 1861724     0 18939904 14778748    0      360448     0

The output from the –k option is as follows:

sml_mem

The amount of memory in bytes that the KMA has available in the small memory request pool. In this pool, a small request is less than 256 bytes.

alloc

The amount of memory in bytes that the KMA has allocated from its small memory request pool to small memory requests.

fail

The number of requests for small amounts of memory that failed.

lg_mem

The amount of memory in bytes that the KMA has available in the large memory request pool. In this pool, a large request is from 512 bytes to 4 Kbytes.

alloc

The amount of memory in bytes that the KMA has allocated from its large memory request pool to large memory requests.

fail

The number of failed requests for large amounts of memory.

ovsz_alloc

The amount of memory that is allocated for oversized requests, which are requests that are greater than 4 Kbytes. These requests are satisfied by the page allocator. Thus, there is no pool.

fail

The number of failed requests for oversized amounts of memory.

Example 24  Checking Kernel Memory Allocation

The following example shows an abbreviated output from the sar -k command.

$ sar -k
SunOS balmy 5.10 Generic_144500-10 sun4v    ...
00:00:04 sml_mem   alloc  fail  lg_mem   alloc  fail  ovsz_alloc  fail
01:00:00 6119744 4852865     0 60243968 54334808   156     9666560     0
02:00:01 6119744 4853057     0 60243968 54336088   156     9666560     0
03:00:00 6119744 4853297     0 60243968 54335760   156     9666560     0
04:00:00 6119744 4857673     0 60252160 54375280   156     9666560     0
05:00:00 6119744 4858097     0 60252160 54376240   156     9666560     0
06:00:00 6119744 4858289     0 60252160 54375608   156     9666560     0
07:00:00 6119744 4858793     0 60252160 54442424   156     9666560     0
08:00:00 6119744 4858985     0 60252160 54474552   156     9666560     0
08:20:00 6119744 4858169     0 60252160 54377400   156     9666560     0
08:40:01 6119744 4857345     0 60252160 54376880   156     9666560     0
09:00:00 6119744 4859433     0 60252160 54539752   156     9666560     0
09:20:00 6119744 4858633     0 60252160 54410920   156     9666560     0
09:40:00 6127936 5262064     0 60530688 55619816   156     9666560     0
10:00:00 6545728 5823137     0 62996480 58391136   156     9666560     0
10:20:00 6545728 5758997     0 62996480 57907400   156     9666560     0
10:40:00 6734144 6035759     0 64389120 59743064   156    10493952     0
11:00:00 6996288 6394872     0 65437696 60935936   156    10493952     0

Average  6258044 5150556     0 61138340 55609004   156     9763900     0

Checking Interprocess Communication

You can use the sar -m command to report interprocess communication activities.

$ sar -m
00:00:00   msg/s  sema/s
01:00:00    0.00    0.00

These figures are usually zero (0.00), unless you are running applications that use messages or semaphores.

The output from the –m option is as follows:

msg/s

The number of message operations (send and receive) per second

sema/s

The number of semaphore operations per second

The following abbreviated example shows output from the sar -m command.

$ sar -m
SunOS balmy 5.10 Generic_144500-10 sun4v    ...
00:00:00   msg/s  sema/s
01:00:00    0.00    0.00
02:00:02    0.00    0.00
03:00:00    0.00    0.00
04:00:00    0.00    0.00
05:00:01    0.00    0.00
06:00:00    0.00    0.00

Average     0.00    0.00

Checking Page-In Activity

You can use the sar -p command to report page-in activity, which includes protection and translation faults.

$ sar -p
00:00:00  atch/s  pgin/s ppgin/s  pflt/s  vflt/s slock/s
01:00:00    0.07    0.00    0.00    0.21    0.39    0.00

The following list describes the reported statistics from the –p option.

atch/s

The number of page faults per second that are satisfied by reclaiming a page currently in memory (attaches per second). Instances include reclaiming an invalid page from the free list and sharing a page of text that is currently being used by another process. An example is two or more processes that are accessing the same program text.

pgin/s

The number of times per second that file systems receive page-in requests.

ppgin/s

The number of pages paged in per second. A single page-in request, such as a soft-lock request (see slock/s) or a large block size, might involve paging-in multiple pages.

pflt/s

The number of page faults from protection errors. Instances of protection faults indicate illegal access to a page and copy-on-writes. Generally, this number consists primarily of copy-on-writes.

vflt/s

The number of address translation page faults per second. These faults are known as validity faults, faults occur when a valid process table entry does not exist for a given virtual address.

slock/s

The number of faults per second caused by software lock requests that require physical I/O. An example of the occurrence of a soft-lock request is the transfer of data from a disk to memory. The system locks the page that is to receive the data so that the page cannot be claimed and used by another process.

Example 25  Monitoring Page-In Activity

The following example shows output from the sar –p command.

$ sar -p
SunOS balmy 5.10 Generic_144500-10 sun4v    ...
00:00:04  atch/s  pgin/s ppgin/s  pflt/s  vflt/s slock/s
01:00:00    0.09    0.00    0.00    0.78    2.02    0.00
02:00:01    0.08    0.00    0.00    0.78    2.02    0.00
03:00:00    0.09    0.00    0.00    0.81    2.07    0.00
04:00:00    0.11    0.01    0.01    0.86    2.18    0.00
05:00:00    0.08    0.00    0.00    0.78    2.02    0.00
06:00:00    0.09    0.00    0.00    0.78    2.02    0.00
07:00:00    0.08    0.00    0.00    0.78    2.02    0.00
08:00:00    0.09    0.00    0.00    0.78    2.02    0.00
08:20:00    0.11    0.00    0.00    0.87    2.24    0.00
08:40:01    0.13    0.00    0.00    0.90    2.29    0.00
09:00:00    0.11    0.00    0.00    0.88    2.24    0.00
09:20:00    0.10    0.00    0.00    0.88    2.24    0.00
09:40:00    2.91    1.80    2.38    4.61   17.62    0.00
10:00:00    2.74    2.03    3.08    8.17   21.76    0.00
10:20:00    0.16    0.04    0.04    1.92    2.96    0.00
10:40:00    2.10    2.50    3.42    6.62   16.51    0.00
11:00:00    3.36    0.87    1.35    3.92   15.12    0.00

Average     0.42    0.22    0.31    1.45    4.00    0.00

Checking Queue Activity

You can use the sar –q command to report the following information:

  • The average queue length while the queue is occupied.

  • The percentage of time that the queue is occupied.

$ sar -q
00:00:00 runq-sz %runocc swpq-sz %swpocc

The output from the –q option is as follows:

runq-sz

The number of kernel threads in memory that are waiting for a CPU to run. Typically, this value should be less than 2. Consistently higher values mean that the system might be CPU-bound.

%runocc

The percentage of time that the dispatch queues are occupied.

swpq-sz

The average number of swapped out processes.

%swpocc

The percentage of time in which the processes are swapped out.

Example 26  Monitoring Queue Activity

The following example shows output from the sar -q command. If the %runocc value is high (greater than 90 percent) and the runq-sz value is greater than 2, the CPU is heavily loaded and response is degraded. In this case, additional CPU capacity might be required to obtain acceptable system response.

# sar -q
SunOS balmy 5.10 Generic_144500-10 sun4v    ...
00:00:00 runq-sz %runocc swpq-sz %swpocc
01:00:00     1.0       7     0.0       0
02:00:00     1.0       7     0.0       0
03:00:00     1.0       7     0.0       0
04:00:00     1.0       7     0.0       0
05:00:00     1.0       6     0.0       0
06:00:00     1.0       7     0.0       0

Average      1.0       7     0.0       0

Checking Unused Memory

You can use the sar -r command to report the number of memory pages and swap-file disk blocks that are currently unused.

$ sar -r
00:00:00 freemem freeswap
01:00:00    2135   401922

The output from the –r option is as follows:

freemem

The average number of memory pages that are available to user processes over the intervals sampled by the command. Page size is system-dependent.

freeswap

The number of 512-byte disk blocks that are available for page swapping.

Example 27  Monitoring Unused Memory

The following example shows output from the sar -r command.

$ sar -r
SunOS balmy 5.10 Generic_144500-10 sun4v    ...
00:00:04 freemem freeswap
01:00:00   44717  1715062
02:00:01   44733  1715496
03:00:00   44715  1714746
04:00:00   44751  1715403
05:00:00   44784  1714743
06:00:00   44794  1715186
07:00:00   44793  1715159
08:00:00   44786  1714914
08:20:00   44805  1715576
08:40:01   44797  1715347
09:00:00   44761  1713948
09:20:00   44802  1715478
09:40:00   41770  1682239
10:00:00   35401  1610833
10:20:00   34295  1599141
10:40:00   33943  1598425
11:00:00   30500  1561959

Average    43312  1699242

Checking CPU Utilization

You can use the sar -u command to display CPU utilization statistics.

$ sar -u
00:00:00    %usr    %sys    %wio   %idle
01:00:00       0       0       0     100

The sar command without any options is equivalent to the sar -u command. At any given moment, the processor is either busy or idle. When busy, the processor is in either user mode or system mode. When idle, the processor is either waiting for I/O completion or has no work to do.

The output from the –u option is as follows:

%usr

The percentage of time that the processor is in user mode

%sys

The percentage of time that the processor is in system mode

%wio

The percentage of time that the processor is idle and waiting for I/O completion

%idle

The percentage of time that the processor is idle and not waiting for I/O

A high %wio value generally means that a disk slowdown has occurred.

Example 28  Monitoring CPU Utilization

The following example shows output from the sar -u command.

$ sar -u
00:00:04    %usr    %sys    %wio   %idle
01:00:00       0       0       0     100
02:00:01       0       0       0     100
03:00:00       0       0       0     100
04:00:00       0       0       0     100
05:00:00       0       0       0     100
06:00:00       0       0       0     100
07:00:00       0       0       0     100
08:00:00       0       0       0     100
08:20:00       0       0       0      99
08:40:01       0       0       0      99
09:00:00       0       0       0      99
09:20:00       0       0       0      99
09:40:00       4       1       0      95
10:00:00       4       2       0      94
10:20:00       1       1       0      98
10:40:00      18       3       0      79
11:00:00      25       3       0      72

Average        2       0       0      98

Checking System Table Status

You can use the sar -v command to report the status of the process table, inode table, file table, and shared memory record table.

$ sar -v
00:00:00  proc-sz    ov  inod-sz    ov  file-sz    ov   lock-sz
01:00:00   43/922     0 2984/4236    0  322/322     0    0/0   

The output from the –v option is as follows:

proc-sz

The number of process entries (proc structures) that are currently being used, or allocated, in the kernel.

inod-sz

The total number of inodes in memory compared to the maximum number of inodes that are allocated in the kernel. This number is not a strict high watermark. The number can overflow.

file-sz

The size of the open system file table. sz is given as 0, because space is allocated dynamically for the file table.

ov

The overflows that occur between sampling points for each table.

lock-sz

The number of shared memory record table entries that are currently being used, or allocated, in the kernel. sz is given as 0 because space is allocated dynamically for the shared memory record table.

Example 29  Monitoring System Table Status

The following abbreviated example shows output from the sar -v command. This example shows that all tables are large enough to have no overflows. These tables are all dynamically allocated based on the amount of physical memory.

$ sar -v
00:00:04  proc-sz    ov  inod-sz    ov  file-sz    ov   lock-sz
01:00:00   69/8010    0 3476/34703    0    0/0       0    0/0   
02:00:01   69/8010    0 3476/34703    0    0/0       0    0/0   
03:00:00   69/8010    0 3476/34703    0    0/0       0    0/0   
04:00:00   69/8010    0 3494/34703    0    0/0       0    0/0   
05:00:00   69/8010    0 3494/34703    0    0/0       0    0/0   
06:00:00   69/8010    0 3494/34703    0    0/0       0    0/0   
07:00:00   69/8010    0 3494/34703    0    0/0       0    0/0   
08:00:00   69/8010    0 3494/34703    0    0/0       0    0/0   
08:20:00   69/8010    0 3494/34703    0    0/0       0    0/0   
08:40:01   69/8010    0 3494/34703    0    0/0       0    0/0   
09:00:00   69/8010    0 3494/34703    0    0/0       0    0/0   
09:20:00   69/8010    0 3494/34703    0    0/0       0    0/0   
09:40:00   74/8010    0 3494/34703    0    0/0       0    0/0   
10:00:00   75/8010    0 4918/34703    0    0/0       0    0/0   
10:20:00   72/8010    0 4918/34703    0    0/0       0    0/0   
10:40:00   71/8010    0 5018/34703    0    0/0       0    0/0   
11:00:00   77/8010    0 5018/34703    0    0/0       0    0/0  

Checking Swapping Activity

You can use the sar -w command to report swapping and switching activity.

$ sar -w
00:00:00 swpin/s bswin/s swpot/s bswot/s pswch/s
01:00:00    0.00     0.0    0.00     0.0      22

The output from the sar –w command is as follows:

swpin/s

The number of LWP transfers into memory per second.

bswin/s

The number of blocks transferred for swap-ins per second. /* (float)PGTOBLK(xx->cvmi.pgswapin) / sec_diff */.

swpot/s

The average number of processes that are swapped out of memory per second. If the number is greater than 1, you might need to increase memory.

bswot/s

The number of blocks that are transferred for swap-outs per second.

pswch/s

The number of kernel thread switches per second.


Note -  All process swap-ins include process initialization.
Example 30  Monitoring Swap Activity

The following example shows output from the sar -w command.

$ sar -w
00:00:04 swpin/s bswin/s swpot/s bswot/s pswch/s
01:00:00    0.00     0.0    0.00     0.0     132
02:00:01    0.00     0.0    0.00     0.0     133
03:00:00    0.00     0.0    0.00     0.0     133
04:00:00    0.00     0.0    0.00     0.0     134
05:00:00    0.00     0.0    0.00     0.0     133
06:00:00    0.00     0.0    0.00     0.0     133
07:00:00    0.00     0.0    0.00     0.0     132
08:00:00    0.00     0.0    0.00     0.0     131
08:20:00    0.00     0.0    0.00     0.0     133
08:40:01    0.00     0.0    0.00     0.0     132
09:00:00    0.00     0.0    0.00     0.0     132
09:20:00    0.00     0.0    0.00     0.0     132
09:40:00    0.00     0.0    0.00     0.0     335
10:00:00    0.00     0.0    0.00     0.0     601
10:20:00    0.00     0.0    0.00     0.0     353
10:40:00    0.00     0.0    0.00     0.0     747
11:00:00    0.00     0.0    0.00     0.0     804

Average     0.00     0.0    0.00     0.0     198

Checking Terminal Activity

You can use the sar -y command to monitor terminal device activities.

$ sar -y
00:00:00 rawch/s canch/s outch/s rcvin/s xmtin/s mdmin/s
01:00:00       0       0       0       0       0       0

If you have a lot of terminal I/O, you can use this report to determine whether any bad lines exist. The output from the sar –y command is as follows:

rawch/s

Input characters (raw queue) per second

canch/s

Input characters that are processed by canon (canonical queue) per second

outch/s

Output characters (output queue) per second

rcvin/s

Receiver hardware interrupts per second

xmtin/s

Transmitter hardware interrupts per second

mdmin/s

Modem interrupts per second

The number of modem interrupts per second (mdmin/s) should be close to zero. The receive and transmit interrupts per second (xmtin/s and rcvin/s) should be less than or equal to the number of incoming or outgoing characters, respectively. If not, check for bad lines.

Example 31  Monitoring Terminal Activity

The following example shows output from the sar -y command.

$ sar -y
00:00:04 rawch/s canch/s outch/s rcvin/s xmtin/s mdmin/s
01:00:00       0       0       0       0       0       0
02:00:01       0       0       0       0       0       0
03:00:00       0       0       0       0       0       0
04:00:00       0       0       0       0       0       0
05:00:00       0       0       0       0       0       0
06:00:00       0       0       0       0       0       0
07:00:00       0       0       0       0       0       0
08:00:00       0       0       0       0       0       0
08:20:00       0       0       0       0       0       0
08:40:01       0       0       0       0       0       0
09:00:00       0       0       0       0       0       0
09:20:00       0       0       0       0       0       0
09:40:00       0       0       1       0       0       0
10:00:00       0       0      37       0       0       0
10:20:00       0       0       0       0       0       0
10:40:00       0       0       3       0       0       0
11:00:00       0       0       3       0       0       0

Average        0       0       1       0       0       0

Checking Overall System Performance

You can use the sar -A command to display statistics from all options to provide a view of overall system performance.

This command provides a more global perspective. If data from more than a single time segment is shown, the report includes averages.