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Clemens Bleile

Creating an Oracle Snapshot Copy PDB on top of ASM

By | Oracle | No Comments

Creating a snapshopt copy Pluggable Database (PDB) on top of Automatic Storage Management (ASM) is not possible, because you need to have a filesystem which supports sparse files. According the following MOS-Note sparse files are supported on Automatic Storage Management Cluster File System (ACFS) since 12.2.: 12.2 Oracle ACFS Sparse Files Enhancements (Doc ID 2200264.1) However, I thought it is more fun to create a PDB Snapshot Copy on a XFS-filesystem, which I wanted to…

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Jérôme Dubar

ODA: Move a DB to ASM after migrating from 11g to 19c

By | Database Administration & Monitoring, Database management, Hardware & Storage, Operation systems, Oracle | No Comments

Introduction Modern Oracle Database Appliances still support 11gR2, but there are several drawbacks using this old version: if you want/need support for your databases, you should pay for Market Driven Support (11gR2 is even no more under extended support – it ended at the end of 2020) some ODA features will not work with 11gR2 (odacli Data Guard feature for example) the use of ACFS filesystems is mandatory As I already told you, it’s more…

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Jérôme Dubar

Disk usage on ODA – Free MB and usable MB

By | Database Administration & Monitoring, Database management, Hardware & Storage, Oracle | No Comments

Introduction Oracle Database Appliances rely on ASM to manage disk redundancy. And ASM is brilliant. Compared to RAID, redundancy is managed at the block level. For NORMAL redundancy, which is similar to RAID1, you need at least 2 disks, but it can also work with 3 disks, 4 disks, 5 disks and so on. There is no need for parity at the disk level. HIGH redundancy, which does not exist in RAID technology, is basically…

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Jérôme Dubar

6 things Oracle could do for a better ODA

By | Cloud, Database Administration & Monitoring, Database management, Hardware & Storage, Operation systems, Oracle | No Comments

Introduction With the latest ODA X8 range, at least 80% of the customers could find an ODA configuration that fits their needs. For the others, either they can’t afford it, either they are already in the Cloud, or they need extremely large storage or EXADATA performance. Among these 80% of customers, only a few choose ODA. Let’s see how Oracle could improve the ODA to make it a must. 1) Make robust and reliable releases…

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Mouhamadou Diaw

Migrating from ASMLIB to ASMFD

By | Database Administration & Monitoring | No Comments

Before Oracle 12.1 the methods used to configure ASM were • udev • asmlib Oracle 12.1 comes with a new method called Oracle ASM Filter Driver (Oracle ASMFD). In Oracle documentation we can find following: Oracle ASM Filter Driver (Oracle ASMFD) is a kernel module that resides in the I/O path of the Oracle ASM disks. Oracle ASM uses the filter driver to validate write I/O requests to Oracle ASM disks. The Oracle ASMFD simplifies…

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Daniel Westermann

udev rules for ASM devices on RHEL 7

By | Database Administration & Monitoring | 2 Comments

Preparing the storage devices for use with ASM is one of the first tasks you should do. When you do not want to use ASMLib then udev is what you should use for this. As the order/naming of the devices in the device tree is not guaranteed (e.g. dm-1 is not guaranteed to be the same device after a reboot of the system) you need a way to fix this and that is what udev…

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Oracle Team

ASM iostats

By | Database Administration & Monitoring | One Comment

By Franck Pachot . A few screenshots and a link here. Sysadmins do not like ASM because they don’t have the tools they like to manage the disks. For example, they don’t want to run SQL queries to check performance, and asmcmd iostat is quite limited. Here is a nice way to get I/O statistics easily from command line.

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Oracle Team

Where is the ASM SPFILE?

By | Database Administration & Monitoring | No Comments

By Franck Pachot . In the previous blog post, to the question “where is the ASM SPFILE” I answered by running ‘asmcmd spget’. But this is available only if the ASM instance is started. If you have corrupted your SPFILE (and it’s easy to do it) you can start with a local PFILE and the CREATE SPFILE= FROM PFILE. But then you get the location of the local one you used. If you need to…

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Oracle Team

Extended clusters and asm_preferred_read_failure_groups

By | Database Administration & Monitoring | One Comment

By Franck Pachot . When you have 2 sites that are not too far you can build an extended cluster. You have one node on each site. And you can also use ASM normal redundancy to store data on each site (each diskgroup has a failure group for each site). Writes are multiplexed, so the latency between the two sites increases the write time. By default, reads can be done from one or the other…

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