Dear Pa Aizen,
Kebetulan saya pakai RHEL5 di production saya (HP ML370 G5 dengan
memory 6 Giga), Centos itu sama dengan RHEL5 dan Oracle Enterprise
Linux 5.
Namun mungkin karena ini versi baru saya sering mengalami system slow
walaupun idle diatas 80%. Dan saya lihat error nya ORA-00379 yaitu ada
masalah dengan buffer dan saya harus flush buffer setiap system slow..
Berikut mungkin ada manfaatnya buat rekan-rekan yang memiliki hal yang
sama dengan saya;
How to Configure RHEL/OEL 5 32-bit for Very Large Memory with ramfs
and HugePages
Follow steps below to perform the configuration:
1. Logon root
2. Configure Linux to mount ramfs over /dev/shm at every boot. Edit
/etc/rc.local and add the following:
# umount /dev/shm
# mount -t ramfs ramfs /dev/shm
# chown oracle:oinstall /dev/shm
#
where oracle is the Oracle owner and oinstall is the group for Oracle
owner account.
3. Reboot server
4. Logon as root
5. Check whether /dev/shm is mounted with type ramfs
# mount | grep shm
ramfs on /dev/shm type ramfs (rw)
#
6. Check permissions of /dev/shm
# ls -ld /dev/shm
drwxr-xr-x 3 oracle oinstall 0 Jul 13 12:12 /dev/shm
#
7. Increase max locked memory limit. Edit /etc/security/limits.conf
and add
* soft memlock 3145728
* hard memlock 3145728
8. Logon to oracle
9. Check max locked mem limit:
$ ulimit -l
3145728
$
11. Configure instance parameters for VLM:
a. Convert DB_CACHE_SIZE, DB_xK_CACHE_SIZE parameters to
DB_BLOCK_BUFFERS
b. Add parameter USE_INDIRECT_DATA_BUFFERS=TRUE
c. Configure SGA size according to the needs
d. Remove SGA_TARGET if set
eRemove MEMORY_TARGET / MEMORY_MAX_TARGET parameters if set (see
Note 749851.1)
12. Startup instance
13. Examine the memory allocation:
$ ls -l /dev/shm
...
$ ipcs -m
...
$
14. Configure hugepages
a. Get Hugepagesize from
$ grep Hugepagesize /proc/meminfo
Hugepagesize: ..... kB
$
b. Compute nr_hugepages using Note 401749.1
c. Set kernel parameter:
# sysctl -w vm.nr_hugepages=<value from above>
...
#
d. Set parameter for every boot. Edit /etc/sysctl.conf for
vm.nr_hugepages=<value from above>
15. Check available hugepages:
$ grep Huge /proc/meminfo
HugePages_Total: ...
HugePages_Free: ...
HugePages_Rsvd: ...
Hugepagesize: ..... kB
$
16. Restart instance
17. Check available hugepages (1 or 2 pages free, some of the total is
reserved)
$ grep Huge /proc/meminfo
HugePages_Total: ...
HugePages_Free: ... (1/2)
HugePages_Rsvd: ...
Hugepagesize: ..... kB
If the setting of nr_hugepages is not effective, you might need to
reboot the server.
Semoga manfaat,
Salam,
WISNU (Newbie)
