Overview of Oracle Flex ASM In Oracle 19c RAC-20220111
Overview of Oracle Flex ASM In Oracle 19c RAC-20220111
導讀：
1.Oracle Flex ASM使Oracle ASM例項能夠在一個獨立的伺服器為更多不同的資料庫提供服務 。
2.Oracle Flex ASM特性：解決了本地asm例項於本地oracle例項強繫結的問題。配置Oracle Flex ASM後：本地asm例項down時，本地oracle例項可隨機分配至其他節點的asm例項中，保證了oracle例項執行的強壯性。
實驗來證明Oracle Flex ASM特性：
本地asm例項down時，本地oracle例項故障轉移驗證。
1.檢視gi版本
[grid@rac3:/home/grid]$sqlplus / as sysasm SQL*Plus: Release 19.0.0.0.0 - Production on Tue Jan 4 21:34:39 2022 Version 19.9.0.0.0 Copyright (c) 1982, 2019, Oracle. All rights reserved. Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production Version 19.9.0.0.0
2.檢視是否開啟oracle flex asm（預設開啟）
[grid@rac3:/home/grid]$asmcmd showclustermode ASM cluster : Flex mode enabled - Direct Storage Access
3.檢視flex asm配置資訊
[grid@rac3:/home/grid]$srvctl config asm ASM home: <CRS home> Password file: +OCR/orapwASM Backup of Password file: +OCR/orapwASM_backup ASM listener: LISTENER ASM instance count: 3 Cluster ASM listener: ASMNET1LSNR_ASM
4.檢視flex asm監聽狀態
[grid@rac3:/home/grid]$lsnrctl status ASMNET1LSNR_ASM LSNRCTL for Linux: Version 19.0.0.0.0 - Production on 04-JAN-2022 20:42:15 Copyright (c) 1991, 2020, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=ASMNET1LSNR_ASM))) STATUS of the LISTENER ------------------------ Alias ASMNET1LSNR_ASM Version TNSLSNR for Linux: Version 19.0.0.0.0 - Production Start Date 04-JAN-2022 20:35:00 Uptime 0 days 0 hr. 7 min. 14 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/19.0.0/grid/network/admin/listener.ora Listener Log File /u01/app/grid/diag/tnslsnr/rac3/asmnet1lsnr_asm/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=ASMNET1LSNR_ASM))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.203)(PORT=1525))) Services Summary... Service "+ASM" has 3 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Instance "+ASM2", status READY, has 1 handler(s) for this service... Instance "+ASM3", status READY, has 2 handler(s) for this service... Service "+ASM_ARCH" has 3 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Instance "+ASM2", status READY, has 1 handler(s) for this service... Instance "+ASM3", status READY, has 2 handler(s) for this service... Service "+ASM_DATA" has 3 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Instance "+ASM2", status READY, has 1 handler(s) for this service... Instance "+ASM3", status READY, has 2 handler(s) for this service... Service "+ASM_OCR" has 3 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Instance "+ASM2", status READY, has 1 handler(s) for this service... Instance "+ASM3", status READY, has 2 handler(s) for this service... The command completed successfully
5.節點3可以訪問節點1的asm例項
[grid@rac3:/home/grid]$sqlplus sys/oracle@192.168.56.201:1525/+ASM as sysasm SQL*Plus: Release 19.0.0.0.0 - Production on Tue Jan 4 20:45:39 2022 Version 19.9.0.0.0 Copyright (c) 1982, 2019, Oracle. All rights reserved. Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production Version 19.9.0.0.0 SQL> select instance_name from v$instance; INSTANCE_NAME -------------------------------- +ASM1 # 正因為節點3可用訪問節點1的asm例項這個特點。進而使flex asm解決了本地asm例項於oracle例項強繫結的問題。 # 配置flex asm後，本地asm例項down時，本地oracle例項可隨機分配至其他節點的asm例項中，保證了oracle例項執行的強壯性。
6.關閉節點3的asm例項，instance例項仍是open
[grid@rac3:/home/grid]$srvctl stop asm -n rac3 節點3的oracle例項仍open，程式ora_smon_racdb3是ok [grid@rac3:/home/grid]$ps -ef | grep smon root 4059 1 1 20:31 ? 00:00:20 /u01/app/19.0.0/grid/bin/osysmond.bin oracle 9036 1 0 20:36 ? 00:00:00 ora_smon_racdb3 grid 31026 5165 0 20:59 pts/0 00:00:00 grep --color=auto smon [grid@rac3:/home/grid]$srvctl status database -d racdb -detail Instance racdb1 is running on node rac1 Instance racdb1 is connected to ASM instance +ASM1 Instance racdb2 is not running on node rac2 <=手動關閉節點2 Instance racdb3 is running on node rac3 Instance racdb3 is connected to ASM instance +ASM1 <=instance從+asm3轉移至+asm1 # 節點3的instance racdb3已連線+asm1例項 節點1透過v$asm_client檢視檢視連線asm例項的資訊 SQL> select INST_ID,instance_name,db_name,status from gv$asm_client order by 2; INST_ID INSTANCE_NAME DB_NAME STATUS ---------- -------------------- ---------------- ------------------------ 1 +ASM1 +ASM CONNECTED 1 +ASM1 +ASM CONNECTED 1 rac1 _OCR CONNECTED 1 racdb1 racdb CONNECTED 1 racdb1 racdb CONNECTED 1 racdb3 racdb CONNECTED 6 rows selected. # instance racdb3已連線+asm1例項（即inst_id=1） # 節點rac3此時asm例項已經down，但是oracle例項仍然open。 # 說明：本地asm例項與本地oracle例項不是強制繫結，本地asm例項是否open對oracle例項影響不是決定的。
7.檢視crs資源節點3的asm例項已offline，但節點3的instance仍是online。
證明：本地asm例項down時，本地oracle例項故障轉移驗證。
[grid@rac3:/home/grid]$crsctl stat res -t -------------------------------------------------------------------------------- Name Target State Server State details -------------------------------------------------------------------------------- Local Resources -------------------------------------------------------------------------------- ora.LISTENER.lsnr ONLINE ONLINE rac1 STABLE ONLINE ONLINE rac2 STABLE ONLINE ONLINE rac3 STABLE ora.chad ONLINE ONLINE rac1 STABLE ONLINE ONLINE rac2 STABLE ONLINE ONLINE rac3 STABLE ora.net1.network ONLINE ONLINE rac1 STABLE ONLINE ONLINE rac2 STABLE ONLINE ONLINE rac3 STABLE ora.ons ONLINE ONLINE rac1 STABLE ONLINE ONLINE rac2 STABLE ONLINE ONLINE rac3 STABLE -------------------------------------------------------------------------------- Cluster Resources -------------------------------------------------------------------------------- ora.ARCH.dg(ora.asmgroup) 1 ONLINE ONLINE rac1 STABLE 2 ONLINE ONLINE rac2 STABLE 3 OFFLINE OFFLINE STABLE # +ASM3關閉，所以例項3服務的磁碟組也會offline ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup) 1 ONLINE ONLINE rac1 STABLE 2 ONLINE ONLINE rac2 STABLE 3 OFFLINE OFFLINE STABLE # +ASM3關閉，所以例項3服務的監聽也會offline ora.DATA.dg(ora.asmgroup) 1 ONLINE ONLINE rac1 STABLE 2 ONLINE ONLINE rac2 STABLE 3 OFFLINE OFFLINE STABLE # +ASM3關閉，所以例項3服務的磁碟組也會offline ora.LISTENER_SCAN1.lsnr 1 ONLINE ONLINE rac1 STABLE ora.OCR.dg(ora.asmgroup) 1 ONLINE ONLINE rac1 STABLE 2 ONLINE ONLINE rac2 STABLE 3 OFFLINE OFFLINE STABLE # +ASM3關閉，所以例項3服務的磁碟組也會offline ora.asm(ora.asmgroup) 1 ONLINE ONLINE rac1 Started,STABLE 2 ONLINE ONLINE rac2 Started,STABLE 3 OFFLINE OFFLINE Instance Shutdown,ST ABLE # +ASM3關閉，所以例項+ASM的服務會offline ora.asmnet1.asmnetwork(ora.asmgroup) 1 ONLINE ONLINE rac1 STABLE 2 ONLINE ONLINE rac2 STABLE 3 OFFLINE OFFLINE STABLE # +ASM3關閉，所以例項3服務的asm network資源也會offline ora.cvu 1 ONLINE ONLINE rac1 STABLE ora.qosmserver 1 ONLINE ONLINE rac1 STABLE ora.rac1.vip 1 ONLINE ONLINE rac1 STABLE ora.rac2.vip 1 ONLINE ONLINE rac2 STABLE ora.rac3.vip 1 ONLINE ONLINE rac3 STABLE ora.racdb.db 1 ONLINE ONLINE rac1 Open,HOME=/u01/app/o racle/product/19.0.0 /db_1,STABLE 2 ONLINE ONLINE rac2 Open,HOME=/u01/app/o racle/product/19.0.0 /db_1,STABLE 3 ONLINE ONLINE rac3 Open,HOME=/u01/app/o racle/product/19.0.0 /db_1,STABLE # flex asm 特性，雖然+ASM3例項不可用，但是rac3資料庫例項由其他asm例項提供服務rac3資料庫例項仍可執行 ora.scan1.vip 1 ONLINE ONLINE rac1 STABLE --------------------------------------------------------------------------------
8.結論
a）oracle 19c 預設的asm儲存選項就是使用flex asm。
b） flex asm解決了本地asm例項於oracle例項強繫結的問題；同時本地asm例項down時，本地oracle例項故障轉移驗證。
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