INSTANCE_TYPE：ASM實例要求此參數為ASM，隱含著將DB_UNIQUE_NAME設置為 ASM.ASM_DISKSTRING：指定在磁盤發現過程應當查找的位置，默認值是NULL。ASM_DISKGROUPS：指定在實例啟動時要自動裝載的磁盤組的名稱，默認值是NULL。 ASM在分配空間時，以AU為單位進行，AU即Allocation units，是組成ASM disk的基本單元。 在Oracle 10gR2中，ASM AU的缺省單位大小是1M，相應的條帶大小是128K。在ASM中，可以通過調整_asm_ausize隱含參數的大小來進行調整，_asm_stripesize控制相應的條帶化參數。 從v$asm_diskgroup視圖可以查詢得到相關的信息： SQL> select group_number,name,sector_size,block_size,allocation_unit_size from v$asm_diskgroup; GROUP_NUMBER NAME SECTOR_SIZE BLOCK_SIZE ALLOCATION_UNIT_SIZE———— —— ———– ———- ——————– 1 ARCHDG 512 4096 1048576 2 DATADG 512 4096 1048576在Oracle Database 11g中，可以通過類似如下語句在創建磁盤組時指定au_size:SQL> CREATE DISKGROUP DATA DISK \\\’/dev/raw/raw15\\\’, \\\’/dev/raw/raw16\\\’,\\\’/dev/raw/raw17\\\’ ATTRIBUTE \\\’au_size\\\’ = \\\’16M\\\’, \\\’compatible.asm\\\’ = \\\’11.1\\\’ \\\’compatible.rdbms\\\’ = \\\’11.1\\\’;ASM允許的相關參數可以從DB的實例中查詢獲得，以下是一系列和asm相關的初始化參數：SQL> SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ FROM SYS.x$ksppi x, SYS.x$ksppcv y WHERE x.indx = y.indx AND x.ksppinm LIKE \\\’%asm%\\\’; NAME VALUE DESCRIB—————————— ——————– ————————————————————asm_diskstring disk set locations for discovery_asm_disk_repair_time 14400 seconds to wait before dropping a failing diskasm_diskgroups disk groups to mount automaticallyasm_power_limit 1 number of processes for disk rebalancing_asm_ausize 1048576 allocation unit size_asm_blksize 4096 metadata block size_asm_acd_chunks 1 initial ACD chunks created_asm_libraries ufs library search order for discovery_asm_maxio 1048576 Maximum size of individual I/O request_asm_allow_only_raw_disks TRUE Discovery only raw devices_asmlib_test 0 Osmlib test event_asm_allow_resilver_corruption FALSE Enable disk resilvering for external redundancy_asmsid asm ASM instance id_asm_wait_time 18 Max/imum time to wait before asmb exits_asm_stripewidth 8 ASM file stripe width_asm_stripesize 131072 ASM file stripe size_asm_droptimeout 60 timeout before offlined disks get dropped (in 3s ticks)_asm_emulmax 10000 max number of concurrent disks to emulate I/O errors_asm_emultimeout 0 timeout before emulation begins (in 3s ticks)_asm_kfdpevent 0 KFDP event 20 rows selected.
