標題: 關于32位linux下ORACLE 最大可用內(nèi)存的疑問 [打印本頁] 作者: rambus 時間: 2007-10-19 16:40 標題: 關于32位linux下ORACLE 最大可用內(nèi)存的疑問 請問在32位的suse 9下安裝ORACLE 10G后,ORACLE最大所能使用的內(nèi)存是否為4G？
為服務器配置了16G內(nèi)存，現(xiàn)在卻僅僅用了一點點，郁悶啊作者: rambus 時間: 2007-10-19 16:56 剛才查了查，很多資料稱32位操作系統(tǒng) ORACLE只支持2G內(nèi)存，不知道是否屬實？？作者: numenhuang 時間: 2007-10-19 17:27
還是用64位吧，32位OS上的Oracle，除非采用特殊的技術，一般sga只能達到1.7G作者: blue_stone 時間: 2007-10-19 21:04
建議使用x86-64 Linux, 如果必須使用32位Linux, 可參考Metalink note 260152.1 Summary About the Large SGA & Address Space on RH Linux
我摘錄重點部分給你:
Configuration 5
* RedHat Advanced Server (RHAS) 2.1 (shmfs/tmpfs)
* RedHat Enterprise Linux (RHEL) 3.0 (shmfs/tmpfs, ramfs)
* Configuration : VLM mode + in-memory filesystem (shmfs/tmpfs, ramfs)
* SGA MAX Size 62GB
* Details in Note 211424.1, Note 262004.1
Since shmfs/tmpfs, ramfs is a memory file system, its size canbe as high as the maximum allowable VM size which is 64GB. SGA MAX Size 62GB theoretic (depending on block size) Only the buffer cache part of the SGA can take advantage of the additional memory. For RHEL3/4 to use the VLM option to create a very large buffercache, you have two options (details in Note 262004.1):
* Use shmfs/tmpfs much as you would in RHAS2.1:
mountNote 262004.1):
* Use shmfs/tmpfs much as you would in RHAS2.1:
mount a shmfs with a certain size to /dev/shm, and set the correct permissions. Keep in mind that in RHEL3, shmfs allocate memory is pageable. Better to use tmpfs since there is no need to specify size.
Mount shmfs:
# mount -t
shm shmfs -o size=20g /dev/shm
Edit /etc/fstab:
shmfs /dev/shm shm size=20g 0 0
---- OR ----
Mount tmpfs:
# mount –t tmpfs tmpfs /dev/shm
Edit /etc/fstab:
none /dev/shm tmpfs defaults 0 0
* Use ramfs (Ref. Note 262004.1, Note 259772.1)
ramfs is similar to shmfs, except that pages are not pageable/swappable. This approach provides the commonly desired effect. Ramfs is created by:
# mount -t ramfs ramfs /dev/shm (unmount /dev/shm first).
The only difference here is that the ramfs pages are not backed by big pages.
* When the shmfs/tmpfs,ramfs is available, Oracle server should know whether to use it or not. Need to use the parameter 'use_indirect_data_buffers=true' remains the same;
If any one of DB_CACHE_SIZE, DB_xK_CACHE_SIZE are set, convert them to DB_BLOCK_BUFFERS
* How to use the memory file system shmfs in short,for details see Note 211424.1:
* Mount the shmfs file system as root using command:
# mount -t shm shmfs -o nr_blocks=8388608 /dev/shm
* Set the shmmax parameter to half of RAM size at most 4294967295
# echo 4294967295 >/proc/sys/kernel/shmmax
* Set the init.ora parameter use_indirect_data_buffers=true
* Startup oracle.
* How to use the memory file system ramfs in short, for details see Note 262004.1:
* Mount the shmfs file system as root using command:
