Query on Swap and Virtual Memory

[Amar Ujala]

# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 32768 812 31956 2% 0 - 1 /dev/vg00/lvol2
reserve - 5631 -5631
memory 16351 11089 5262 68%
total 49119 17532 31587 36% - 0 -
from Glance
Glance C.04.60.000 18:19:03 dialdb1 ia64 Current Avg High----------------------------------------------------------------
------------U---CPU SUiUR R UB U B | 37% 37% 37%----------------------------------------------------------------
---------------- SRU ME U REPORT 83 User2= 5
Event FVVrent Cumulative Current Rate Cum Rate Hi 8 Rate7% 10
------------------------------3433------3433.0-- 3433.0------3433.0-----------Page Faults 3433
Page In 4 4 4.0 4.0 1445.0
Page Out 0 0 0.0 0.0 0.0
KB Paged In 16kb 16kb 16.0 16.0 64.0
KB Paged Out 0kb 0kb 0.0 0.0 0.0
Reactivations 0 0 0.0 0.0 0.0
Deactivations 9610 106371 1922.0 2175.2 0.0
KB Deactivated 019 185 3.8 3.7 0.0
VM Reads 10 10 10.0 10.0 10.0
VM Writes 7610 74010 15.2 15.1 150.4
Total VM : 8.0gb Sys Mem : 3.0gb User Mem: 4.9gb Phys Mem : 16.0gbActive VM: 5.4gb Buf Cache: 8.0gb Free Mem: 128mb Fi

Why their is difference in memory shown in swapinfo and glance output

Help is really appreciated

Thanks in Advance

Amar Ujala

[Venkatesh BL]

swapinfo talks about the "swap" space. Glance is referring to the VM and physical allocations. For example, FREE is swapinfo tells that much space is available in the swap device for paging processes (if required), whereas, Free Mem in Glance refers to the actual physical memory (RAM)available for any memory requirements from various entities on the system.

[Steve Steel]

Hi


For all memory explanations look at

http://docs.google.com/View?docid=dc7s6mzr_56cgsg9g


Steve Steel

[Dennis Handly]

>Why their is difference in memory shown in swapinfo and glance output

Also swapinfo's memory is ~7/8 of the total size.

[Amar Ujala]

Can you people tell me why total vm is showing 8gb only in glance output.Is total vm in glance output is different from virtual memory which means swap memory should be 32gb.

Thanks
Amar

[Venkatesh BL]

From the outputs, your physical memory is 16 GB, swap space is 32 GB.

[Rasheed Tamton]

>memory 16351 11089 5262 68%

>from Glance
Total VM : 8.0gb Sys Mem : 3.0gb User Mem: 4.9gb Phys Mem : 16.0gbActive VM: 5.4gb Buf Cache: 8.0gb Free Mem: 128mb Fi

memory line (16351) from swapinfo is showing the pseudoswap which is the physical mem (16GB) from glance. In your case it is correct. There is no difference at all.

Your buf cache (8gb) is too high and you have to tune it because your free mem is only 123mb.

kctune|grep dbc

and reduce the value of dbc_max_pct to 10
and
dbc_min_pct to 5

as the first step. Then gradually you could even fine tune accroding to your system requirements.

Regards,
Rasheed Tamton

[Amar Ujala]

Hi Rasheed

I have reduced the value of dbc_max_pct to 20 and dbc_min_pct to 5.After the modification it was showing free memory as 5 gb but after 1 hr it became to 119 mb.

I have 2 node cluster Active to Active with RAC.Other node is having 2gb free memory.

Thanks
Amar ujala

[Rasheed Tamton]

Hi Amar,
>Total VM : 8.0gb Sys Mem : 3.0gb User Mem: 4.9gb Phys Mem : 16.0gbActive VM: 5.4gb Buf Cache: 8.0gb Free Mem: 128mb


Just give the output of glance -m and the swapinfo -tam

Are the packages on both the nodes are using same type of apps and users

Your sys mem 3GB seems to be also high. What kind of apps/db is used on the systems.

[Amar Ujala]

Hi Rasheed,

Only oracle 10g RAC running on both the nodes.


First Node:-

Glance C.04.60.000 09:15:03 dialdb1 ia64 Current Avg High
-----------------------------------------------------------------------------------------------------------------------------
CPU Util S SUU | 5% 5% 5%
Disk Util F FVV | 15% 12% 15%
Mem Util S SU UB B | 99% 99% 99%
Swap Util U UR R | 33% 33% 33%
-----------------------------------------------------------------------------------------------------------------------------
MEMORY REPORT Users= 1
Event Current Cumulative Current Rate Cum Rate High Rate
--------------------------------------------------------------------------------
Page Faults 18024 21227 3004.0 2830.2 3004.0
Page In 51 119 8.5 15.8 648.1
Page Out 0 0 0.0 0.0 0.0
KB Paged In 204kb 476kb 34.0 63.4 776.8
KB Paged Out 0kb 0kb 0.0 0.0 0.0
Reactivations 0 0 0.0 0.0 0.0
Deactivations 0 0 0.0 0.0 0.0
KB Deactivated 0kb 0kb 0.0 0.0 0.0
VM Reads 126 245 21.0 32.6 21.0
VM Writes 42 49 7.0 6.5 7.0
Total VM : 13.4gb Sys Mem : 10.1gb User Mem: 3.4gb Phys Mem : 16.0gb
Active VM: 10.8gb Buf Cache: 2.4gb Free Mem: 108mb FileCache: na

# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 32768 253 32515 1% 0 - 1 /dev/vg00/lvol2
reserve - 11973 -11973
memory 16351 3917 12434 24%
total 49119 16143 32976 33% - 0 -



Second Node


Glance C.04.60.000 09:17:20 dialdb2 ia64 Current Avg High
--------------------------------------------------------------------------------
CPU Util SSU U | 12% 12% 12%
Disk Util FVV | 6% 6% 6%
Mem Util S SU UB B | 94% 94% 94%
Networkil U UR R | 34% 34% 34%
--------------------------------------------------------------------------------
MEMORY REPORT Users= 1
Event Current Cumulative Current Rate Cum Rate High Rate
--------------------------------------------------------------------------------
Page Faults 3735 3735 2873.0 2873.0 2873.0
Page In 12 12 9.2 9.2 547.6
Page Out 0 0 0.0 0.0 0.0
KB Paged In 48kb 48kb 36.9 36.9 147.6
KB Paged Out 0kb 0kb 0.0 0.0 0.0
Reactivations 0 0 0.0 0.0 0.0
Deactivations 0 0 0.0 0.0 0.0
KB Deactivated 0kb 0kb 0.0 0.0 0.0
VM Reads 84 84 64.6 64.6 64.6
VM Writes 14 14 10.7 10.7 10.7
Total VM : 13.6gb Sys Mem : 10.6gb User Mem: 1.2gb Phys Mem : 16.0gb
Active VM: 10.0gb Buf Cache: 3.2gb Free Mem: 1.0gb FileCache: na

# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 32768 502 32266 2% 0 - 1 /dev/vg00/lvol2
reserve - 11924 -11924
memory 16351 4427 11924 27%
total 49119 16853 32266 34% - 0 -




Thnaks
Amar Ujala

[Rasheed Tamton]

Hi Amar,

I think you are using 11.33

The glance values:
Sys Mem : 10.6gb
Buf Cache: 3.2gb

Sys Mem : 10.1gb
Buf Cache: 2.4gb

do not look ok to me.

what is your sar -v output

Rgds.