Category Archives: Engineered Systems

Category about Oracle Engineered Systems

Exadata version 23.1.0.0.0 – Part 01

On 08/March/2023 the Oracle Exadata team released version 23.1.0.0.0 and this include a significant change, OEL 8. But is not just that, other interesting requirements are there and I will discuss them below. I will show you how to patch to the 23.1 version and some other details as well. In this first part, I will just discuss one interesting point that you need to take care of before you start to patch. And probably is more important than you imagine.

Before you patch

The new version brings some requirements (over what you need to be running) to allow you to patch. For the Grid Infrastructure, you need to run 19.15 or a newer version. You can even run the 21c (21.6 or newer) version if you want. If you want to know how to do that, I already discussed how to upgrade both in previous posts (19c, and 21c).

For databases, the recommendation is the same, 19c or 21c. You can still run older versions (11,g, 12c, and 18) but they are already (or will be soon) under Market Driver Support. You can read the MOS note over that (here), but to be clear (now) only the 19c have premier support available.

And now things became quite interesting because the new 23.1 version is the first running with OEL 8. And if you check the supplemental README for the 23.1 version just the 19c support the database and GI are listed. So, be aware and check the compatibilities.

One important detail for this version is that you can only upgrade to 23.1 if your base Exadata running version is newer or equal to 21.2.10 (basically one year old only). If not, you need to upgrade to (at least) this version before you patch to 23.1. And this will be the same in the one-year future, it will be only possible to upgrade to 24.x if you will be running (at least) 23.1.

If you are running the old Exadata with InfiniBand, your dom0 will always be updated until Oracle Linux 7 with UEK5. For domU you can upgrade to the OEL 8. And you can upgrade in any order, first dom0 or domU. If you are running RoCE, your dom0 can run the latest OEL 8 UEK6. The blog post from Oracle made an excellent explanation about the upgrade paths and below you can see the images that are there (I used the image from their post).

So, as usual, the version includes everything, switches, storage, and database node. And while for switches and storages, the patches are quite normal, for virtualized environments the upgrades paths start to be a little more challenging to plan. I will explain, but (as hinted in the blog post) the upgrade of the Hosts and Guests independently and in any order. And is hard not because of the patch apply itself, but will be to create the plan. Remember the requirements for Oracle Database and GI? So, you can spend a lot of time patching others parts than the Exadata version.

But let’s put pieces together, the small lines written in several places. With this version 23.1, Oracle is telling you that you need to be running at least the Oracle Database 19c to be allowed to have a continuous upgrade for future releases (and possible usage) of Exadata. And whatever the machine version that you use, IB or RoCE network. You can’t anymore use GI older than 19.15, and the databases are enforced, as well, to be this version too. Imagine that you have some kind of incapability between 11g/12c and OEL 8, if you need to open one SR, you need to have/pay for that support, and will not be cheap.

And if you think the upcoming 23c (and that it will be the new LTS version) being in OEL 8 is a requirement. Imagine one year in the future, when the Exadata 24.x version will arrive, do you think that Oracle still supports 11g to the new OEL 9? I don’t think so.

And by the way, IMHO you should be running to 19c. 11G is from 2009, 12.1 from July 2013. So, they are old and out of support for good reasons. I understand the point that they are working on and the legacy applications that maybe you have. But the point is not just to support them, is the case to be possible to continue to upgrade/update your Exadata. Please do not postpone your database upgrades anymore, for the good sake of your Exadata. 

 

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Exadata, REQUIRED_MIRROR_FREE_MB and GRID 19.16

Starting with Grid Infrastructure/ASM 19.16 Oracle changed how the REQUIRED_MIRROR_FREE_MB is calculated and the impact is more than expected. Check below examples of the changes, and how this will impact you. This is valid for all GI/ASM starting with 19.16 and only for Exadata/ExaCC.

Please read my new post about this issue.

REQUIRED_MIRROR_FREE_MB

The REQUIRED_MIRROR_FREE_MB (according to 19c documentation) is:

amount of space that must be available in a disk group to restore full redundancy after the worst failure that can be tolerated by the disk group without adding additional storage. This requirement ensures that there are sufficient failure groups to restore redundancy”.

And (at Exadata environment until 19.16) is calculated based on the disk redundancy that you have. If you choose the HIGH, the raw size of two disks (the largest in your diskgroup) is reserved; at NORMAL, is the raw size of one disk. At Exadata, it differs from other environments because does not consider the whole failgroup failure and the way that extends are written/spread (more info below and in another post).

But for now, understand that the required size is what you need to reserve (as raw space) at your diskgroup to ensure protection in case of disk failure. And it is directly related to the USABLE_FILE_MB because the space that you can allocate at your diskgroup (USABLE_FILE_MB) comes from (FREE_MB- REQUIRED_MIRROR_FREE_MB)/redundancy factor (3 for HIGH, 2 for NORMAL). So, when you increase the REQUIRED_MIRROR_FREE_MB you reduce the USABLE_FILE_MB. I will explain more later.

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Oracle Engineered Systems since 2010

Recently I made a tweet about a new project with Oracle Engineered System (X9M) that remembered me about what I made with these systems until now. So, this opened the opportunity to tell my background and history until now working with these systems. Is not a show-off of ego boost post.

 

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Upgrade AHF and TFA at Exadata

Quick post for today. Recently needed to upgrade to the last version of Autonomous Health Framework (AHF) from an Exadata running GI 19.5. In this particular case the GI was not even running AHF, but still using the standalone TFA that comes with it. So, here I will show how to upgrade to the last version of AHF and replacing the TFA as well.

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Fixing Exadata Missing Volumes at LVM

Recently during the Exadata patch, one database node reported an issue during the patchmgr and stopped the patch apply. The error was related to missing volumes (LVDoNotRemoveOrUse) at LVM. During the post, you can check the error, but please take attention that it changes some LVM config file contents. So, check correctly the step executed and (if possible) open pro-active SR to be sure what you will be doing.

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Exadata, dracut and LVM locking_type as read-only

Sometimes even a perfectly running server can pass over issues after a simple reboot. And was exactly that occurred recently with one Exadata database node. And was not the first time that the same error appears (and since there is no well-documented step by step to fix it I documented them below). So, check how to fix the issue related to the read-only locking_type of LVM detected by dracut.

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Duplicate, Restore and ZDLRA

From time to time we need to clone/duplicate some databases and we have several ways to do that, most common are duplicate and restore (with a new name) commands. But when using RMAN catalogs we need to take extra care because we can up lose the backups of the entire database because of the wrong way to do that. And this is even more crucial when using ZDLRA.

You need to choose between The Good and The Bad. Because if you choose wrong you will have troubles with The Ugly. The key factor here is the RMAN/ZDLRA catalog, choose wrong and you will automatically add bad data in the internal catalog tables and if you will try to clean, can delete database backups.

In this post, I will show how correctly clone one database when you are using the RMAN/ZDLRA catalog and the reasons for that. I will show the problems and the collateral effects for ZDLRA when you choose the bad way.

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ZDLRA, RA_CLIENT_CONFIG_FILE channel parameter

When we are enrolling a database at ZDLRA we need to configure the RMAN channel parameters to point to our definitions like RA_WALLET and CREDENTIAL_ALIAS. The same is done for backup and restore channels. But this can be done in a different way using RA_CLIENT_CONFIG_FILE for ra_library.

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MOVE_BACKUP and ZDLRA

As I wrote previously, sometimes we need to have long-term/archival backups due to some compliance. And usually, these backups are stores outside (like a vault/bunker) but for sure not at the same datacenter as the database. But how we can do this at ZDLRA?

In my post about COPY_BACKUP, I wrote how to have an external copy of one backup set at ZDLRA. But this is not the best option when we need to archive some backup because it continues to follow the same recovery window as the original backup set. This means that if you need to have some kind of archive for 5 years, you need to define your recovery window (at the policy level) to this window. And for sure this will put high pressure on space usage because all backups will be stored until became obsolete.

So, the best way is to use the KEEP backups from rman. And as I wrote in my previous post, they not interact/broke with the incremental forever strategy. Is possible to generate the keep backup, and using the DBMS_RA.MOVE_BACKUP moves these backups to a filesystem destination (and further you can copy/store) and archive it outside of ZDLRA.

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