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Old 12-07-2018, 09:32 AM   #1
redhatwannabe
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Does a swap usage of 100% indicates swapping despite low memory usage?


Dear all,

I've the following output

Code:
[oracle@camden-db ~]$ date
Fri Dec  7 14:59:34 CET 2018
[oracle@camden-db ~]$ swapon -s
Filename                                Type            Size    Used    Priority
/dev/dm-0                               partition       2097148 2043464 -1
[oracle@camden-db ~]$ free
              total        used        free      shared  buff/cache   available
Mem:       32782584     4856440      238444     7808012    27687700    19788028
Swap:       2097148     2043464       53684
[oracle@camden-db ~]$ date
Fri Dec  7 14:59:44 CET 2018
https://www.wikihow.com/Check-Swap-Space-in-Linux

Quote:


In either of the above, look for the used space, compared to the total size. If a large percentage of the swap space is used, then one of two actions may be warranted: you may want to either add an additional swap disk to increase the available swap space, or you may want to add additional physical memory to the system.
based on the above can I said that the disk is currently going swapping due to large percentage of swap space being used compare to total swap space

total swap space is 2097148 KB, used swap space is 2043464. nearly 100%, but then should we take note of memory usage as well?

Note total memory is 32782584 KB while usage is only 4856440 KB.

Code:
32782584     4856440
many thanks in advance!
 
Old 12-07-2018, 09:48 AM   #2
berndbausch
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Swap space is 2GB, that's tiny compared to your 32GB RAM. While I am not too knowlegeable about memory management algorithms in Linux, here are the scenarios I imagine:

At some point in time, memory management decided that dirty pages had to be removed from RAM and copied them to swap space. Memory pressure went down since that moment, but as those pages have not been accessed since, they continue to live on swap space.

While only 4-5GB memory is used for applications, the buffer cache occupies some 26GB. Again, there may have been a lot of file I/O in the past, which inflated the buffer cache. If applications don't need more memory, the situation remains as it is.
Or file I/O continues to be strong, in which case it is hard to "compress" the buffer cache.

The output of vmstat and iostat might help clarify what's going on.
 
Old 12-07-2018, 10:17 AM   #3
redhatwannabe
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Code:
[oracle@camden-db ~]$ 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 2043488 258280 180632 27491076    0    0   835    84    0    0  1  0 98  0  0
[oracle@camden-db ~]$ iostat
Linux 3.10.0-229.el7.x86_64 (camden-db.philips.com)    12/07/2018      _x86_64_(8 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.42    0.00    0.38    0.16    0.00   98.03

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.29         1.04         2.21   63769238  134692875
sdb               4.25      1524.35         3.11 93083026825  190000332
sdc               0.00         0.00         0.00       1897         40
sdd               4.91      1133.55        34.69 69218799893 2118036120
sde               8.61      1550.01        84.98 94649971421 5189431524
sdf               8.27      1586.66        76.89 96887884481 4695472208
sdg              10.37       800.71        57.67 48894645361 3521616744
sdh               0.00         0.00         0.00       1189          4
sdi               0.93        53.06       412.72 3240315705 25202503792
dm-0              0.11         0.27         0.17   16698356   10557880
dm-1              0.29         0.77         2.03   47042742  124132915

[oracle@camden-db ~]$
thanks a lot!
 
Old 12-07-2018, 10:28 AM   #4
berndbausch
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You should run them repeatedly, e.g. 20 times every 5 seconds:
Code:
vmstat 5 20
iostat 5 20
 
Old 12-07-2018, 10:50 AM   #5
redhatwannabe
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Code:
[oracle@camden-db ~]$ vmstat 5 20
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 2  0 2043548 302048 187576 27474096    0    0   835    84    0    0  1  0 98  0  0
 0  0 2043548 302008 187596 27474104    0    0     0    51 1170 2147  0  0 100  0  0
 0  0 2043548 301580 187632 27474096    0    0     0    78 1234 2154  1  0 99  0  0
 0  0 2043548 301932 187652 27474096    0    0     0    37 1083 2068  0  0 100  0  0
 1  0 2043548 301932 187668 27474104    0    0     0    21 1067 2045  0  0 100  0  0
 0  0 2043548 301808 187688 27474104    0    0     0    27 1133 2065  1  0 99  0  0
 0  0 2043548 301296 187704 27474108    0    0     0    21 1179 2184  0  0 99  0  0
 0  0 2043548 301244 187720 27474036    0    0     0    27 1188 2062  1  0 98  0  0
 0  0 2043548 301244 187752 27474040    0    0     0    27 1083 2078  0  0 100  0  0
 0  0 2043548 300624 187768 27474048    0    0     0    32 1235 2126  1  0 99  0  0
 0  0 2043548 300672 187776 27474048    0    0     0    14 1073 2058  0  0 100  0  0
 0  0 2043548 300548 187800 27474048    0    0     0    22 1101 2042  1  0 99  0  0
 0  0 2043548 300548 187816 27474040    0    0     0    27 1081 2062  0  0 100  0  0
 0  0 2043548 300532 187832 27474056    0    0     0    17 1126 2058  1  0 99  0  0
 0  0 2043548 300548 187848 27474056    0    0     0    64 1089 2069  0  0 100  0  0
 0  0 2043548 300548 187880 27474064    0    0     0    30 1127 2060  1  0 99  0  0
 0  0 2043548 302052 187896 27474036    0    0     0    29 1097 2082  0  0 100  0  0
 0  0 2043548 304548 187920 27474032    0    0     0    35 1166 2099  1  0 99  0  0
 0  0 2043548 304236 187952 27474100    0    0     0    31 1118 2098  0  0 100  0  0
 0  0 2043548 304080 187968 27474112    0    0     0    39 1188 2138  1  0 99  0

iostat

Code:
[oracle@camden-db ~]$ iostat 5 20
Linux 3.10.0-229.el7.x86_64 (camden-db.philips.com)    12/07/2018      _x86_64_        (8 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.42    0.00    0.38    0.16    0.00   98.03

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.29         1.04         2.21   63769246  134696860
sdb               4.25      1524.31         3.11 93083042645  190005296
sdc               0.00         0.00         0.00       1897         40
sdd               4.91      1133.51        34.69 69218801817 2118098068
sde               8.61      1549.97        84.98 94649975253 5189595228
sdf               8.27      1586.62        76.89 96887898189 4695626276
sdg              10.37       800.69        57.67 48894678969 3521799512
sdh               0.00         0.00         0.00       1189          4
sdi               0.93        53.06       412.71 3240315705 25202503792
dm-0              0.11         0.27         0.17   16698356   10557940
dm-1              0.29         0.77         2.03   47042742  124136840

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.10    0.00    0.10    0.00    0.00   99.80

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               1.40         0.00        18.40          0         92
sde               1.20         0.00        16.80          0         84
sdf               0.60         0.00         3.20          0         16
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.49    0.00    0.70    0.05    0.00   95.75

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.20         0.00         1.60          0          8
sdc               0.00         0.00         0.00          0          0
sdd               1.40         0.00        11.20          0         56
sde              23.60         0.00       600.00          0       3000
sdf              23.20         0.00       593.60          0       2968
sdg               0.40         0.00         1.60          0          8
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           4.12    0.00    1.29    0.05    0.00   94.54

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.20         0.00         0.60          0          3
sdb               0.60         1.60         3.20          8         16
sdc               0.00         0.00         0.00          0          0
sdd               1.00         0.00        12.80          0         64
sde              14.60         0.00      1749.60          0       8748
sdf              14.20         0.00      1742.40          0       8712
sdg               0.40         0.00         3.20          0         16
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.20         0.00         0.60          0          3

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.03    0.00    0.50    0.00    0.00   98.47

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.40         0.00         3.20          0         16
sdb               0.20         0.00         1.60          0          8
sdc               0.00         0.00         0.00          0          0
sdd               0.20         0.00         3.20          0         16
sde               5.00         0.00       624.80          0       3124
sdf               4.60         0.00       620.80          0       3104
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.60         0.00         3.20          0         16

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.51    0.00    0.18    0.03    0.00   98.29

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.20         0.00         7.20          0         36
sdb               0.40         0.00         2.40          0         12
sdc               0.00         0.00         0.00          0          0
sdd               1.00         0.00        10.40          0         52
sde               3.60         0.00        28.00          0        140
sdf               3.60         0.00        23.20          0        116
sdg               3.80         0.00        32.80          0        164
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.20         0.00         7.20          0         36

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.50    0.00    0.18    0.00    0.00   99.32

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               1.60         0.00        16.80          0         84
sde               1.80         0.00        32.00          0        160
sdf               1.40         0.00        25.60          0        128
sdg               2.20         0.00        16.80          0         84
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.60    0.00    0.13    0.00    0.00   99.27

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.80         0.00         6.40          0         32
sdc               0.00         0.00         0.00          0          0
sdd               0.60         0.00         6.40          0         32
sde               0.80         0.00         8.80          0         44
sdf               1.00         0.00         8.00          0         40
sdg               0.40         0.00         2.40          0         12
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.20    0.00    0.10    0.03    0.00   99.67

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.40         0.00         2.40          0         12
sdc               0.00         0.00         0.00          0          0
sdd               0.80         0.00         8.80          0         44
sde               1.00         0.00         9.60          0         48
sdf               1.40         0.00         9.60          0         48
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.63    0.00    0.10    0.00    0.00   99.27

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               1.20         0.00         6.00          0         30
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               1.00         0.00         9.60          0         48
sde               0.80         0.00         9.60          0         48
sdf               0.00         0.00         0.00          0          0
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              1.40         0.00         6.00          0         30

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.33    0.00    0.08    0.00    0.00   99.60

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.60         0.00        12.00          0         60
sdb               0.20         0.00         1.60          0          8
sdc               0.00         0.00         0.00          0          0
sdd               0.20         0.00         3.20          0         16
sde               0.80         0.00         6.40          0         32
sdf               0.20         0.00         0.80          0          4
sdg               0.40         0.00         1.60          0          8
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.80         0.00        12.00          0         60

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.70    0.00    0.13    0.00    0.00   99.17

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.40         0.00         3.20          0         16
sdc               0.00         0.00         0.00          0          0
sdd               0.80         0.00         8.80          0         44
sde               1.00         0.00        10.40          0         52
sdf               0.60         0.00         4.00          0         20
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.23    0.00    0.08    0.00    0.00   99.70

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.20         0.00         2.40          0         12
sdb               0.40         0.00         2.40          0         12
sdc               0.00         0.00         0.00          0          0
sdd               0.80         0.00         8.80          0         44
sde               1.00         0.00        10.40          0         52
sdf               0.60         0.00         4.00          0         20
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.20         0.00         2.40          0         12

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.68    0.00    0.13    0.00    0.00   99.20

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               0.60         0.00         5.60          0         28
sde               0.20         0.00         3.20          0         16
sdf               0.00         0.00         0.00          0          0
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.18    0.00    0.10    0.03    0.00   99.70

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               0.80         0.00         8.80          0         44
sde               1.00         0.00        10.40          0         52
sdf               0.60         0.00         3.20          0         16
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.60    0.00    0.15    0.00    0.00   99.25

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.20         0.00         0.30          0          1
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               0.80         0.00         8.80          0         44
sde               1.00         0.00        10.40          0         52
sdf               0.20         0.00         0.80          0          4
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.20         0.00         0.30          0          1

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.35    0.00    0.08    0.00    0.00   99.57

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.40         0.00         3.20          0         16
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               0.20         0.00         3.20          0         16
sde               0.80         0.00         6.40          0         32
sdf               0.60         0.00         3.20          0         16
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.40         0.00         3.20          0         16

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.70    0.00    0.10    0.00    0.00   99.20

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.40         0.00         2.40          0         12
sdb               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               0.80         0.00         8.80          0         44
sde               0.80         0.00         9.60          0         48
sdf               0.00         0.00         0.00          0          0
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.40         0.00         2.40          0         12

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.23    0.00    0.13    0.00    0.00   99.65

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.20         0.00         1.60          0          8
sdc               0.00         0.00         0.00          0          0
sdd               0.80         0.00         8.80          0         44
sde               1.20         0.00        11.20          0         56
sdf               0.80         0.00         4.00          0         20
sdg               0.00         0.00         0.00          0          0
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.78    0.00    0.18    0.03    0.00   99.02

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.60         0.00         4.00          0         20
sdc               0.00         0.00         0.00          0          0
sdd               4.40         0.00        40.00          0        200
sde               1.60         0.00        18.40          0         92
sdf               1.00         0.00         6.40          0         32
sdg               1.00         0.00        11.20          0         56
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0
many thanks in advance!
 
Old 12-07-2018, 06:45 PM   #6
berndbausch
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vmstat shows
Code:
------cpu-----
us sy id wa st
1  0  98  0  0
which means the CPU is almost 100% idle. If it were waiting for disk I/O, including I/O to and from swap space, you would see a non-zero value in the fourth column, "wa", but that's not the case.

vmstat also shows a sustained but very moderate bo value ("block out", meaning disk output), but no swap activity.

iostat shows idleness most of the time, except for ten or fifteen seconds of I/O on sde and sdf.

In summary, at the time you made this measurement, the system was essentially idle. Does this match your observations? I believe the measurements confirm my theory that your swap space use indicates that memory was under pressure some time ago, and the buffer cache size indicates that there has been file I/O, but currently the system looks rather stable.

If, all of a sudden, you started large memory users, you would first see the buffer cache shrink. If, at the same time, you also cause heavy file I/O, you would see a "fight" for RAM between the processes and buffer cache.
 
1 members found this post helpful.
Old 12-07-2018, 07:46 PM   #7
syg00
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If it worries you simply swapoff/swapon and keep an eye on it in future. See if you can pick a correlation between system activity and swap usage.
 
Old 12-08-2018, 10:34 AM   #8
redhatwannabe
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Dear berndbausch,

yes the server is idle most of the time. Just because the swap space does not met the requirements doesn't mean swapping will occur most of the time. If the server is idle most of the time even a low swap space will only mean a short instance of swapping.


vmstat also shows a sustained but very moderate bo value ("block out", meaning disk output), but no swap activity.
is there any figure for moderate bo value?

iostat shows idleness most of the time, except for ten or fifteen seconds of I/O on sde and sdf.
are you referring to these time instances:

Code:
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.49    0.00    0.70    0.05    0.00   95.75

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
sdb               0.20         0.00         1.60          0          8
sdc               0.00         0.00         0.00          0          0
sdd               1.40         0.00        11.20          0         56
sde              23.60         0.00       600.00          0       3000
sdf              23.20         0.00       593.60          0       2968
sdg               0.40         0.00         1.60          0          8
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           4.12    0.00    1.29    0.05    0.00   94.54

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.20         0.00         0.60          0          3
sdb               0.60         1.60         3.20          8         16
sdc               0.00         0.00         0.00          0          0
sdd               1.00         0.00        12.80          0         64
sde              14.60         0.00      1749.60          0       8748
sdf              14.20         0.00      1742.40          0       8712
sdg               0.40         0.00         3.20          0         16
sdh               0.00         0.00         0.00          0          0
sdi               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.20         0.00         0.60          0          3
I also understand want to know why iostat is being invoked to check for swapping instead of just relying only on vmstat

thanks a lot!
 
Old 12-08-2018, 06:03 PM   #9
berndbausch
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“moderate” is my subjective judgment. Disks can transfer much more than 80 blocks per second (I think a block is 1K).

I suggested iostat to see if there is any pressure to keep a large buffer cache, i.e. file I/O. Indeed I meant the peak you mention, perhaps the kernel is sync’ing a few buffer cache blocks, or the application initiated some I/O at this point.
 
Old 12-09-2018, 08:42 AM   #10
onebuck
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Member Response

Hi,

Maybe this will help you; https://www.howtoforge.com/tutorial/linux-swappiness/

This is a informational link to help you with server usage not desktop.

Hope this helps.
Have fun & enjoy!
 
  


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