The solution to the problem that Oracle hugepages are not used, causing the server to be too laggy

reason ：
It's too laggy to use through user reaction , After receiving the fault report , Login to the server requires almost 1 Minutes to connect , Let's take a brief look at the performance of the server , Development IO Very low 、 There is still a lot of memory left , At least there is 1GB above , either page in / page out, And the most obvious phenomenon is CPU Utilization is quite high , Keep it all the time 100%, meanwhile CPU Utilization SYS part , Both in 95% above , Due to insufficient physical memory , Page exchange is ongoing , Use swap Space .

By looking at oracle alert The log found that the large page memory was not used
view alert.log

Starting ORACLE instance (normal)************************ Large Pages Information *******************
Per process system memlock (soft) limit = 64 KB
Total Shared Global Region in Large Pages = 0 KB (0%)

Large Pages used by this instance: 0 (0 KB)
Large Pages unused system wide = 15362 (30 GB)
Large Pages configured system wide = 15362 (30 GB)Large Page size = 2048 KB
RECOMMENDATION:
  Total System Global Area size is 30 GB. For optimal performance,
  prior to the next instance restart:  1. Large pages are automatically locked into physical memory.
 Increase the per process memlock (soft) limit to at least 30 GB to lock 100% System Global Area's large pages into physical memory
********************************************************************

Solution steps ：
1. Check if it is set HugePages
cat /etc/sysctl.conf

cat /etc/sysctl.conf
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576

vm.nr_hugepages = 15362

result ： Have configuration HugePages

2. See if you want to set memlock unlimited

#<domain>      <type>  <item>         <value>
#

#*               soft    core            0
#*               hard    rss             10000
#@student        hard    nproc           20
#@faculty        soft    nproc           20
#@faculty        hard    nproc           50
#ftp hard nproc 0
#@student        -       maxlogins       4

*      soft    nofile    131072
*      hard    nofile    131072
*      soft    nproc    131072
*      hard    nproc    131072

result ： Didn't add
processing method ： Add at the end oracle soft memlock unlimited oracle hard memlock unlimited

3. Restart the database 、 Restart the machine .
View correspondence alert There will be... In the log “Large Pages Information” Content ：
cat alert.log | grep -A 3 “Large Pages Information”

--  No settings unlimited Previous logs 
oracle soft memlock unlimited
oracle hard memlock unlimited
************************ Large Pages Information *******************
Per process system memlock (soft) limit = 64 KB

-- Set up memlock unlimited After the log 
Total Shared Global Region in Large Pages = 0 KB (0%)
--
************************ Large Pages Information *******************
Per process system memlock (soft) limit = UNLIMITED

Total Shared Global Region in Large Pages = 30 GB (100%)

4. confirm HugePages Set up the success
View about HugePages Information about ：

[[email protected] ~]$ grep Huge /proc/meminfo
AnonHugePages:      6144 kB
HugePages_Total:   15362
HugePages_Free:      563
HugePages_Rsvd:      562
HugePages_Surp:        0
Hugepagesize:       2048 kB

** result ：** From logs and grep Huge /proc/meminfo Look at HugePages Used normally , The server is also back to normal .