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Benefits of Zstandard Compression in Oracle 23ai HCC

In Oracle Database 23ai, significant improvements have been made to Hybrid Columnar Compression (HCC), with the default compression method now utilizing Zstandard (Zstd) instead of the previous algorithms, zlib and bzip2. But what exactly is Zstandard, and how does it differ from zlib and bzip2? Zstandard is a lossless data compression algorithm developed by YannContinue reading “Benefits of Zstandard Compression in Oracle 23ai HCC”

How to patch Exadata PDU

Recently, I collaborated with a colleague to promote our Exadata system to a new Oracle Enterprise Manager (OEM) server. However, we encountered issues when attempting to promote the Power Distribution Unit (PDU). After consulting My Oracle Support (MOS), we decided to address potential bugs by applying the latest PDU patch before proceeding with the promotionContinue reading “How to patch Exadata PDU”

What should we do if the Flash Cache is degraded in an Exadata cell

Flash cache plays a critical role in Exadata performance. When issues arise, it’s crucial to understand the symptoms and resolution steps. Typically, each flash cache comprises four flash disks. If one flash disk fails, the cell service automatically removes it while continuing to operate with the remaining three disks. In most cases, immediate intervention isContinue reading “What should we do if the Flash Cache is degraded in an Exadata cell”

ZDLRA ERROR: Filesystem label ESP is found more than once.

Recently, while patching a ZDLRA X7-2 full stack to version 21.1.202405, I encountered an error during the dbnode precheck. This blog post details the issue and its resolution. The Error During the precheck, the following error was encountered: 2024-09-17 15:13:11 +0200 :ERROR : dbnodeupdate.sh precheck failed on one or more nodes SUMMARY OF WARNINGS ANDContinue reading “ZDLRA ERROR: Filesystem label ESP is found more than once.”

Exadata, How to unlock ilom’s root account

After upgrading to ILOM 5.x, password locking is enabled. So root account could be locked after you change password, especially you forgot change it in oem. You can find more detail in Doc ID 2670512.1 . If the root account is locked, you must unlock and changing password cannot unlock the account. As you cannotContinue reading “Exadata, How to unlock ilom’s root account”

How to create new VM in Exadata

In my exadata environnment, it has 2 compute nodes, 3 cells, 3 VM clusters.Let’s see how to add new VMs cluster .First, add new IPs in DNS server. In my case: exavm01clu04: 172.22.1.241 exavm02clu04: 172.22.1.242 exavm01clu04-vip:172.22.1.244 exavm02clu04-vip:172.22.1.243 scan: 172.22.1.245 172.22.1.246 172.22.1.247 Second, downloading new OEDA(Patch 30640393) , start oeda server and create new VM configContinue reading “How to create new VM in Exadata”

Exadata, How to change ilom root password

For security raison, we need to change dbnode/cell ilom root password regularly. Let’s login to Ilom and change password. > ssh exa01-ilom Password: Oracle(R) Integrated Lights Out Manager Version 4.0.4.52.a r139829 Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved. Warning: HTTPS certificate is set to factory default. Hostname: exa01-ilom -> set /SP/users/root passwordContinue reading “Exadata, How to change ilom root password”

Oracle 19, recover standby become easier

Since oracle 19 , recover standby become quite easier. Here my dataguard configuration and it shows ORA-16810 error. DGMGRL> show configuration Configuration – ora19_cfg Protection Mode: MaxPerformance Members: ora19_pri – Primary database ora19_stb – Physical standby database Error: ORA-16810: multiple errors or warnings detected for the member Fast-Start Failover: Disabled Configuration Status: ERROR (status updatedContinue reading “Oracle 19, recover standby become easier”

Exadata, how to change ilom nameserver by ipconf in cell

You have to stop cell service properly before you change ilom network config in cell. You can find the procedure at How to restart cell services properly I propose you use ipconf to update your network config in exadata system. Don’t use ilom command line , because it doesn’t change /opt/oracle.cellos/cell.conf file, and you will haveContinue reading “Exadata, how to change ilom nameserver by ipconf in cell”

Exadata, how to backup domU

Backup user domaine machine (domU) is quite easy in Exadata system. 1. Pause the DomU [root@db01-m ~]# xm list Name ID Mem VCPUs State Time(s) Domain-0 0 8571 4 r—– 15546936.0 vm01db01.mydomaine.local 48 180227 22 -b—- 56705.8 … root@db01-m ~]# xm pause vm01db01.mydomaine.local [root@db01-m ~]# xm list Name ID Mem VCPUs State Time(s) Domain-0 0Continue reading “Exadata, how to backup domU”