Category Archives: Storage Server

Exadata and ZDLRA, Patch Exadata Stack

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The process to patch Exadata stack and software changed in the last years and it became easier. Now, with patchmgr to be used for all (database servers, storage cells, and switches) the process is much easier to control the steps. Here I will show the steps that are involved in this process.

Independent if it is ZDLRA or Exadata, the process for Engineering System is the same. So, this post can be used as a guide for the Exadata patch apply as well. In 2018 I already made a similar process about how to patch/upgrade Exadata to 18c (you can access here) and even made a partial/incomplete post for 12c in 2015.

The process will be very similar and can be done in rolling and non-rolling mode. In the first, the services continue to run and you don’t need to shutdown databases, but will take more time because the patchmgr applies server by server. At the second, you need to shutdown the entire GI and the patch is applied in parallel and will be faster.

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Exadata X8M, Workshop

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When Exadata X8M was released during the last Open World I made one post about the technical details about it. You can check it here: Exadata X8M (this post received some good shares and reviews). If you read it, you can see that I focused in more internal details (like torn blocks, one side path, two sides read/writes, and others), that differ from the normal analyses for Exadata X8M.

But recently I was invited by Oracle to participate exclusive workshop about Exadata X8M and I needed to share some details that picked me up. The workshop was done directly from Oracle Solution Center in Santa Clara Campus (it is an amazing place that I had an opportunity to visit in 2015, and have a rich history – if you have the opportunity, visit), and cover some technical details and with the hands-on part.

Unfortunately, I can’t share everything (I even don’t know if I can share something), but see the info below.

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Exadata, Missing Metric

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Understand metrics for Exadata Storage Server is important to understand how all the software features are being used and all the details from that. Here I will discuss one case where the FC_IO_BY_R_SEC metric can show not precise values. And I will discuss one missing metric that can save a lot.

If you have doubts about metrics, you can check my post about metrics, it was an introduction, but cover some aspects of how to read and use it. You can check my other post where I show how to use metric DB_FC_IO_BY_SEC to identify database problems that can be hidden when checking only from the database side.

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Exadata, Understanding Metrics

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Metrics for Exadata deliver to you one way to deeply see, and understand, what it is happening for Exadata Storage Server and Exadata Software. Understand it is fundamental to identify and solve problems that can be hidden (or even unsee) from the database side. In this post, I will explain details about these metrics and what you can do using them.

My last article about Exadata Storage Server metrics was about one example of how to use them to identify problems that do not appear in the database side. In that post, I showed how I used the metric DB_FC_IO_BY_SEC to identify bad queries.

The point for Exadata (that I made in that article), is that most of the time, Exadata is so powerful that bad statements are handled without a problem because of the features that exist (flashcache, smartio, and others). But another point is that usually, Exadata is a high consolidated environment, where you “consolidate” a lot of databases and it is normal that some of them have different workloads and needs. Using metrics can help you to do a fine tune of your environment, but besides that, it delivers to you one way to check and control everything that’s happening.

In this post, I will not explain each metric one by one, but guide you to understand metrics and some interesting and important details about them.

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Exadata, Using metrics to help you

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It is well known that Exadata delivers a lot of power for databases and, besides that, has a lot of features that can be combined to reach the desired goals. But you need to understand how to use Exadata, it is not just knowing the internal hardware pieces, put some SQL hints, or use smart scan that makes a better DBA (or DMA).

Think about the “traditional” environment (DB + storage) and how you check for performance problems there. Basically, you just have/receive the number of IOPS from luns, throughput in MB/s, and latency from the storage side. But Exadata provides a lot of metrics that go beyond that and can be used to really understand what it is happening between the database and the access of data blocks.

For me, one of the most underrated (and not even well explained in web) features of Exadata is the metrics because they can help you to really understand Exadata deeply. As an example, from metrics, you can check the MB/s read from flash cache, disks (per type), flash log writes, reads that bypassed flash cache and went to disk, Smart I/O per database, PDB or consumer groups. It is not part of this post explain all the metrics (will be in another one), but you can read more at Chapter 6 of the Exadata User Guide.

In this post, I will show you one example of how to use the metric to identify and solve database problems. Sometimes it can be a hide and seek game, but I will try to show you how to use metrics and how they can help you on your daily basis.

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Shrink ASM Diskgroup and Exadata Grid Disks

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Here I will cover the shrink of ASM diskgroup in Exadata environment running VM’s. The process here is the opposite of what I wrote in the previous post, but have a tricky part that demands attention to avoid errors. The same points that you checked for extending are valid now: number the cells, disks per cell, ASM mirroring, and the VM that you want to change continue to be important, but we have more now. Besides that, the post shows how to verify (and “fix”) if you have something in the ASM internal extent map that can block the shrink.

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Increase size for Exadata Grid Disks

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A quick article about a maintenance task for Oracle Exadata when you are using OVM and you divided your storage cell disks for every VM. Here I will show you how to extend your Grid Disks to add more space in your ASM diskgroup.

The first thing is being aware of your environment, before everything you need to know the points below because, they are important to calculate the new space, and to avoid do something wrong:

  • Number of cells in your appliance.
  • Number of disks for each cell.
  • Mirroring for your ASM.
  • The VM that you want to add the space.

The “normal” Exadata storage cell has 12 disks, the Extreme Flash version uses 8 disks per storage. If you have doubt about how many disks you have per storage cell, you can connect in each one and check the number of celldisks you have. And before continuing, be aware of Exadata disk division:

To do this change we execute three major steps: ASM, Exadata Storage, and ASM again.

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Exadata X8, Second look

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Every year Oracle arrives and release new version of Exadata with a plenty of new things. We have the natural evolution from hardware (more memory, more cpu…) and sometimes news features from software side. The point for this post today it is not about the HW and SW things, but something is hidden in the small lines of the new X8.

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Aplicando Patch no Exadata

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O appliance Oracle Exadata é uma das tecnologias mais modernas para banco de dados Oracle, a união de Hardware e Software. Mas este software precisa ser atualizado de tempos em tempos você precisa aplicar o patch.

O time de Engineered Systems da Oracle disponibiliza os updates para serem aplicadas em toda a pilha: do Exadata Software aos binários do banco de dados. É tarefa do DMA acompanhar isso e deixar seu ambiente atualizado, muitas vezes (aqui no Brasil) estes updates são aplicados pelo time de ACS da Oracle, mas nada impede que você mesmo faça isso.

Este é o foco destes artigos, vou mostrar como proceder com um update completo do Oracle Exadata: Exadata Software, Infiniband, Linux, Update do Grid 11GR2 para 12C e Aplicação de BP nos binários do banco. Eu já descrevi sobre isso no meu blog a uns 3 anos atrás (aqui e aqui), mas muita coisa mudou desde aquela época.

Planejamento

De qualquer forma, antes de começar qualquer update (Oracle Exadata ou não) temos que planejar, verificar qual a versão que estamos e qual queremos aplicar.

Para o Oracle Exadata temos uma nota que contempla tudo isso e que é o início de qualquer update: Exadata Database Machine and Exadata Storage Server Supported Versions (Doc ID 888828.1). Nesta nota estão todas as informações importantes como documentação, as versões existentes, versões recomendadas e matriz de compatibilidade entre Exadata Software e binários do banco.

Então, o primeiro passo é o planejamento, ler e compreender esta nota, principalmente com as versões disponíveis e quais serão aplicadas. Outro ponto fundamental do planejamento é conhecer o seu ambiente, no meu caso a imagem que tenho aqui é a 11.2.3.3.0.

No tópico Exadata Storage Server 12c da nota identificamos que a última versão e que será aplicada aqui é a 12.1.2.1.2 (image version 12.1.2.1.2.150617.1) e composta pelos seguintes patches e docs:

  • Patch 20748218 – Storage server e InfiniBand
  • Patch 21151982 – Database server (para quem não utiliza OVM)
  • Readme – Note 2014306.1

Na mesma nota temos as versões do Grid Infrastructure e dos bancos de dados que são compatíveis com as imagens do Exadata. Como o meu planejamento inclui atualizar tudo para a última versão estes também serão atualizados.

Através da nota os seguintes updates serão realizados (e demonstrados aqui nestes artigos):

  • Update da imagem 11.2.3.3.0 para a 12.1.2.1.2 do Exadata (storage e bancos)
  • Upgrade da versão 11.2.0.4 BP 6 do Grid para a versão 12.1.0.2 BP 9
  • Update da versão 11.2.0.4 BP6 do banco de dados para a versão 11.2.0.4 BP 16

Pensando no appliance Oracle Exadata e na relação entre seus componentes o primeiro ponto a ser atualizado é a própria imagem do Exadata Storage Server (Linux, Exadata Software). Depois temos switchs Infiniband. Na sequência temos o update dos Database Servers e seus componentes (Grid e os binários do banco de dados).

Antes de iniciar o update precisamos montar o plano de atualização, qual a ordem de instalação dos patches. Isso só pode ser feito lendo todos os Readmes dos patches que vamos aplicar. Lendo o Readme do Patch 20748218 e Patch 21151982 descobrimos que existem dois métodos possíveis para atualizar o Database Server.

O primeiro é através da imagem ISO que acompanha o Patch 21151982 e o segundo é através da criação do repositório Exadata local. Este último método é o que utilizarei aqui, ele tem algumas vantagens que descreverei em detalhes depois mas é importante entender como funciona. Basicamente você cria um repositório local com os rpm’s que serão aplicados (os mesmo presentes na ISO). Infelizmente esta criação pode demorar um pouco e por isso será o primeiro procedimento a ser realizado.

Através da leitura de todas as notas do MOS envolvidas e de todos os Readmes dos patches aplicados o seguinte plano foi criado:

  1. Criação do repositório Exadata para Database Server
  2. Update do Storage Server e Switch Infiniband
  3. Update do Database Server
  4. Upgrade do GRID para 12C e Instalação dos binários 12C
  5. Update dos binários 11.2.0.4 para o BP16

Abaixo a descrição detalhas de cada uma destas etapas acima listadas.

A última atualização deste artigo foi em 03/08/2015.

Patch Storage Server e Infiniband

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O procedimento descrito aqui contempla a atualização da imagem 11.2.3.3.0 para a imagem 12.1.2.1.2 do Oracle Exadata. Aqui estão descritos os procedimentos para o update do Storage Server e Switch Inifiband.

Primeiro Passo Principal

O primeiro passo de qualquer update para Oracle Exadata é ler o Readme da versão e ler o tópico “Know Issues” que lista todos os possíveis erros que você pode encontrar. Isso não quer dizer que outros erros não podem acontecer, mas você tem um local com a solução dos erros conhecidos. Então leia a Nota 2014306.1.

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