Oracle's close transparent large page

Method One:

1, set/etc/grub.conf file, add Transparent_hugepage=never, in system boot is disabled

[Email protected] ~]# cat/etc/grub.conf
# grub.conf generated by Anaconda
#
# Note that you don't have the to rerun grub after making changes to the This file
# notice:you has a/boot partition. This means
# all kernel and INITRD paths is relative to/boot/, eg.
# root (hd0,0)
# kernel/vmlinuz-version RO root=/dev/sda2
# initrd/initrd-[generic-]version.img
#boot =/DEV/SDA
Default=0
Timeout=5
Splashimage= (hd0,0)/grub/splash.xpm.gz
Hiddenmenu
Title Red Hat Enterprise Linux 6 (2.6.32-573.el6.x86_64)
Root (hd0,0)
kernel/vmlinuz-2.6.32-573.el6.x86_64 ro Root=uuid=57f7184b-2dec-43b1-b0cd-9862a4b42cfe Rd_NO_LUKS KEYBOARDTYPE=pc Keytable=us Lang=en_us. UTF-8 rd_no_md sysfont=latarcyrheb-sun16 rd_no_lvm rhgb quiet rd_no_dm rhgb quiet memmap=0x2000000$0x3e000000 nmi_ watchdog=2 crashkernel=256m-:256m printk.time=1 console=ttys0,115200 console=tty0 transparent_hugepage=never # #添加到 Tty0 back, note leave a space
Initrd/initramfs-2.6.32-573.el6.x86_64.img

2. Restart the server

3, check whether to close

# grep Anonhugepages/proc/meminfo

If The output contains a line like "Anonhugepages:
XXXX KB ", with a value of > 0kB, the kernel is using Transparent hugepages.

Method Two:

1. Edit/etc/rc.local Add the following memory

[root]# cat/etc/rc.local
If Test-f/sys/kernel/mm/transparent_hugepage/enabled; Then
echo Never >/sys/kernel/mm/transparent_hugepage/enabled
Fi
If Test-f/sys/kernel/mm/transparent_hugepage/defrag; Then
echo Never >/sys/kernel/mm/transparent_hugepage/defrag
Fi

2. Restart the server

3, check whether to close

# grep Anonhugepages/proc/meminfo

If The output contains a line like "Anonhugepages:
XXXX KB ", with a value of > 0kB, the kernel is using Transparent hugepages.

Add:

1: Starting from Redhat 6, OEL 6, SLES One and UEK2 kernels, the system lacks the capital to enable Transparent Hugepages: Performance to improve memory management transparent large pages (Transparent hugepages) and previous versions The large pages in this feature are similar. The main difference is: Transparent hugepages can be configured in real time, do not need to restart to take effect configuration;

2:transparent Huge pages is not supported in 32-bit Rhel 6.

Transparent Huge Pages is not available on the 32-bit version of RHEL 6.

3:oracle officially does not recommend that we use Redhat 6, OEL 6, SLES One and UEK2 kernels when opening transparent large pages (Transparent hugepages), because transparent large pages (Transparent hugepages ) There are some problems:

1. Transparent large pages (Transparent hugepages) in a RAC environment can cause abnormal node restarts, and performance issues;

2. In a stand-alone environment, transparent large pages (Transparent hugepages) can also cause some abnormal performance problems;

Transparent hugepages memory is enabled by default with Red Hat Enterprise Linux 6, SUSE Linux Enterprise Server One D Oracle Linux 6 with earlier releases of Oracle Linux Unbreakable Enterprise Kernel 2 (UEK2) kernels. Transparent hugepages memory is disabled in later releases of Oracle Linux UEK2 Kernels. Transparent hugepages can cause memory allocation delays during runtime. To avoid performance issues, Oracle recommends, the Disable Transparent hugepages on all Oracle Database servers. Oracle recommends that is instead use, hugepages for enhanced performance. Transparent hugepages memory differs from standard hugepages memory because the kernel khugepaged thread allocates memory dynamically during runtime. Standard hugepages memory are pre-allocated at startup, and does not the change during runtime.

Starting with RedHat 6, OEL 6, SLES One and UEK2 kernels, Transparent Hugepages is implemented and enabled (default) in an Attempt to improve the memory management. Transparent Hugepages is similar to the Hugepages, which has been available in previous Linux releases. The main difference is, the Transparent hugepages is set to dynamically at run time by the khugepaged thread in Kerne L while the regular hugepages had is preallocated at the boot up time. Because Transparent Hugepages is known to cause unexpected node reboots and performance problems with RAC, Oracle Strongl Y advises to disable the use of Transparent hugepages. In addition, Transparent hugepages could cause problems even in a single-instance database environment with unexpected PERFO Rmance problems or delays. As such, Oracle recommends disabling Transparent Hugepages on all Database servers running Oracle.

4: You must also turn off the transparent large page feature when installing Vertica Analytic database

Oracle's close transparent large page