Remove Exadata Flash Grid disk and configure as normal Flash

In previous blog we have created Grid Disk on Flash Disk. Here we are removing Flash Grid Disk and configuring normal Flash Cache.


Remove or move database or any contents to some another ASM Disk group


Drop ASM disk group which was create on flash disk


Drop all the flash grid disk

CellCLI> drop griddisk all prefix=flashdisk force

GridDisk FlashDisk_FD_00_exa1cel01 successfully dropped
GridDisk FlashDisk_FD_01_exa1cel01 successfully dropped
GridDisk FlashDisk_FD_02_exa1cel01 successfully dropped
GridDisk FlashDisk_FD_03_exa1cel01 successfully dropped
GridDisk FlashDisk_FD_04_exa1cel01 successfully dropped
GridDisk FlashDisk_FD_05_exa1cel01 successfully dropped
GridDisk FlashDisk_FD_06_exa1cel01 successfully dropped
GridDisk FlashDisk_FD_07_exa1cel01 successfully dropped


Configure Exadata Flash Disk as Grid Disk

We can use Flash Cache as Grid Disk to create the ASM disk group and can keep the database on flash disk but this is not reccomended solution as flash cache performs better to cache frequently access data rather than creating database on it.

If you want put your database on Flash cache than below are the steps to configure FLASH CACHE as ASM disk.


1. Drop existing flash cache
2. Create flashcache with required size
3. Create grid disk from Flash Cache
4. Create ASM disk group on top of the Flash Griddisk
5. Put your database on ASM disk group which has been configured from Flash grid disk


CellCLI>drop flashcache

If it gives error like below

CELL-02769: Cannot complete flash cache drop on: FD_03_ex01cceladm03. 
Received error: CELL-02732: There may be data not synchronized to the grid disks (dirty data) in flash cache.
Use ALTER FLASHCACHE to flush the dirty data and to stop caching, and then retry the command.

This error comes because flash cache mode has been configured as writeback hence some of the dirty data are still not written to the grid disks.

To overcome from this error flush all the flashcache

CellCLI>  alter flashcache all flush
Flash cache exa1cel01_FLASHCACHE altered successfully

CellCLI> drop flashcache 
Flash cache exa1cel01_FLASHCACHE successfully dropped 


Oracle Exadata default passwords

When Exadata get deployed,  by default it configured with Oracle standard username and password. As per good practice you should always change default password once Exadata handed over to you from Oracle. Below is the list of default Users and Passwords for Exadata.

Database Server


Database server ILOMs


Exadata Storage Cell Server

Exadata Storage Cell Server ILOMs

How to enable Exadata writeback Flashcache on cell storage ? (WriteThrough to WriteBack)

Steps to enabling the Flashcache mode:

This can be done in rolling as well as non-rolloing manner.

First check flashcache mode with below command on all cell servers with the use of dcli utility on DB node. It can be check on cell each server also with cellcli utility.

dbnode1#dcli -l root -g cellgroup "cellcli -e list cell detail" | grep "flashCacheMode" flashCacheMode:          WriteThrough flashCacheMode:          WriteThrough flashCacheMode:          WriteThrough flashCacheMode:          WriteThrough flashCacheMode:          WriteThrough flashCacheMode:          WriteThrough flashCacheMode:          WriteThrough


Also we can find flashcache mode in each cell by executing below command:

cellcli>list cell detail

flashCacheMode: WriteThrough     --->Currently flashCacheMode configured as WriteThrough


Now drop flashcache on each cell server: (If you are following rolling manner then do one by one on each cell server)

cellcli> drop flashcache


Be sure asmdeactivationoutcome is YES before disabling grid disk

CellCLI> list griddisk attributes name,asmmodestatus,asmdeactivationoutcome


Oracle Exadata vs IBM Power Systems

Cost comparison for business decision-makers between Oracle Exadata and IBM power system

The FactPoint Group is a Silicon Valley-based research, and consulting firm that is dedicated to the business improvement of its clients.Factpoint Group has conducted survey for Exadata vs IBM Power system with the help of customers as well as technical team who are using these systems.

The research produce TCO comparison for both the systems which includes:

  • Acquisition costs
  • Implementation and deployment costs
  • Operations and maintenance costs for three years.
Below are the major points which were included in the research.

Implementation Cost

As per  research Oracle Exadata require 59% fewer man-hours than the traditional IBM system.

Implementation Time

Implementation of Exadata can be completed within one week where IBM system requires 3 week for implementation.

Operation and Maintenance labor