Secure Erase of an Exadata System

What has to be done when the Lifecycle of an Exadata System comes to the end.

You need to do an secure erase of DB and Storage nodes.

By the way you can also secure erase the Switches and PDU, etc. but this is not described in this article.

Documentation

https://docs.oracle.com/cd/E80920_01/DBMSQ/exadata-secure-erase.htm#DBMSQ-GUID-DE6BBDF7-6BCB-412B-AD1E-E0FFEEFCC3AA

and  My Oracle Support Doc ID 2180963.1

Steps to do

I use the method via bootable USB Stick

Download Boot Image via Patch 25470974

You need a complete list of all DB and Storage node names including all IP addresses of each ILOM Server

Tip: Before you start reset the password on each Server for example „welcome1“

Prepare USB Stick

I use my Mac book and do a „dd“ to copy the image to the USB Stick

dd if=image_diagnostics_12.2.1.1.0_LINUX.X64_170126.2-1.x86_64.usb of=/dev/disk2

Start a ILOM Web Console Login for the first Server

In parallel start a ILOM terminal console session to do a restart of the first Server

While the reset is running the Web  Console came up with the BIOS Splash screen. Please  enter


<CTRL+P>

It takes a while and you see the boot menu

Select the USB Stick and press enter to start

the Boot Screen appears

Now it is time to check the output on the ILOM terminal console. You will see after a while a „login:“ prompt


Login as "root" password "sos1exadata" or "sos1Exadata"

If the password doesn’t work contact Oracle Support for help

Weiterlesen „Secure Erase of an Exadata System“

Advertisements

Exadata Flash Cache enabled for Write Back

During Tests for an Migration of a major customer application we saw in our AWR reports that most of the jobs are very write intensive. This was the point where we would like to test what happens when we change the Flash Cache Mode from Write Through to Write Back.

What are the main benefits of Write Back mode:

  • it improves the write intensive operations while writing to flash cache is faster than writing to normal Hard disks
  • on Exadata X3  and newer machines write performance can be improved up to 20X IOPS
  • The Write Back Flash Cache accelerates reads and writes for all workloads

First of all I take a look in Metalink and found a Doc ID 1500257.1 with more details.

What are the requirements?

since April 2017 it is default if the following conditions are full filled:

  • Grid and RDBMS Home
    • 11.2.0.4.1 or higher
    • 12.1.0.2 or higher
    • 12.2.0.2 or higher

and

  • DATA diskgroup has HIGH redundancy

When should I use Write Back?

  • It makes sense if your application is write intensive
  • You find significant waits for „free buffer waits“
  • High IO times to check for write bottlenecks in AWR reports

What are the steps to enable Write Back?

We have the possibility to do it „offline“ so we stop the whole Grid & Rdbms Stack, but you can change it also in a Rolling manner.

  • Actual Flash Cache Mode

dcli -g cell_group -l root "cellcli -e list cell attributes flashcachemode"
cel04: WriteThrough
cel05: WriteThrough
cel06: WriteThrough
cel07: WriteThrough

  • Stop the whole Cluster

crsctl stop cluster -all -f

  • Check State of Flash Cache

name: cel04_FLASHCACHE
status: normal

name: cel05_FLASHCACHE
status: normal

name: cel06_FLASHCACHE
status: normal

name: cel07_FLASHCACHE
status: normal

  • Steps for the Change

These steps has to be done on every Cell Server here as an example

Drop the flash cache on that cell

CellCLI> drop flashcache;
Flash cache cel04_FLASHCACHE successfully dropped.

Shut down Cell service

CellCLI> alter cell shutdown services cellsrv;
Stopping CELLSRV services... The SHUTDOWN of CELLSRV services was successful.

Change Cell Flash Cache mode to Write Back

CellCLI> alter cell flashCacheMode=writeback;
Cell cel04 successfully altered 

Restart the Cell Service

CellCLI> alter cell startup services cellsrv;
Starting CELLSRV services...
The STARTUP of CELLSRV services was successful.

Recreate the Flash Cache

CellCLI> create flashcache all;
Flash cache cel04_FLASHCACHE successfully created

Finally check the State on all Cell Server dcli -g cell_group -l root "cellcli -e list cell attributes flashcachemode"
cel04: WriteBack
cel05: WriteBack
cel06: WriteBack
cel07: WriteBack

So the first step was done and now the tests can go on.

In a few weeks I will give a feedback what are the real improvements so stay tuned.

 

 

 

 

Exdata Lifecycle / Patching

patching_icon

Operate an Exadata Database Machine means you have to manage the Lifecyle. One major task is the regular patching of the whole Exa Stack.

This blog article give you an overview about the Patching.

First remember which components are part of the lifecycle.

Following the component and the tool.

exadata

  • GRID & RDBMS
    • opatch (oplan)
  • DB Node
    • patchmgr (that’s new since Oct 2015)
  • Storage Grid
    • patchmgr
  • Network
    • patchmgr

Before starting the Patching you need to do a bullet proof planing otherwise you fail.

For a Quarter Rack with lets say 10 Production databases you need a planing phase of more or less 2-3 weeks.

How to setup a recommendation?

  • Analyze your ORACLE_HOMES
  • Check existing SR for every database
  • Meet with your Application Manager
  • Use Oracle Tools like exachk
  • Use the conflict analyzer in MOS

exachk will be your best friend

Check the My Oracle Support Note 1070954.1 and install the latest version

First take a look of the table of contents

exachk_0

and one very important table is the recommended version overview

exachk_1

What will be the best recommendation?

It doesn’t give an easy answer while Oracle has a lot of possibilities for the Patching:

  • the QFSDP the Quarterly Full Stack Download Patch
  • or Standalone Patchsets for every Component like Infinband, Cell Server, DB-Node and so on

So the decision has to be taken by the whole team of Application Manager and Oracle DBA’s and System Administrator

Weiterlesen „Exdata Lifecycle / Patching“