Storage Administration - Oracle Exadata Recipes: A Problem-Solution Approach - page 287

9-11. Creating Flash Grid Disks for Permanent Storage
Problem
You wish to utilize Exadata's storage server PCI Flash cards for permanent database file storage to improve I/O
performance for specific database objects.

Solution
Generally speaking, database storage on Exadata is stored on the physical SAS disks inside the Exadata storage cells
and the PCI flash is configured for Smart Flash Cache and Smart Flash Logging functionality. However, Oracle does
allow an Exadata DMA to configure a storage server's PCI flash storage for use of permanent database storage in order
to optimize specific types of I/O operations. This is achieved by creating flash-based grid disks in your storage cells
and using these flash grid disks in Oracle ASM disk groups. In this recipe, we will show you how to do the following:
Drop your flash cache in preparation for creating flash-based grid disks

•

• Create flash-based grid disks on your storage cells

• Recreating flash cache with the remaining flash capacity

• Build Oracle ASM disk groups on your flash storage

• Create an Oracle tablespace on your flash-based disk groups and test the performance impact

of querying similar data from flash versus SAS disk storage

Follow these steps:

1. Begin by logging in to a compute node as an operating system account that has SSH trust

configured with the storage cells and listing the details of your flash cache using cellcli ;
in the following example, we will use the oracle Linux account:

[oracle@cm01dbm01 ~]$ dcli -g ./cell_group cellcli -e list flashcache attributes
name,size,celldisk
cm01cel01: cm01cel01_FLASHCACHE 364.75G
FD_05_cm01cel01,FD_02_cm01cel01,FD_06_cm01cel01,FD_07_cm01cel01,FD_13_cm01cel01,
FD_01_cm01cel01,FD_08_cm01cel01,FD_11_cm01cel01,FD_15_cm01cel01,FD_12_cm01cel01,
FD_14_cm01cel01,FD_10_cm01cel01,FD_00_cm01cel01,FD_04_cm01cel01,FD_03_cm01cel01,
FD_09_cm01cel01
cm01cel02: cm01cel02_FLASHCACHE 364.75G
FD_11_cm01cel02,FD_07_cm01cel02,FD_14_cm01cel02,FD_06_cm01cel02,FD_04_cm01cel02,
FD_05_cm01cel02,FD_02_cm01cel02,FD_01_cm01cel02,FD_10_cm01cel02,FD_08_cm01cel02,
FD_00_cm01cel02,FD_03_cm01cel02,FD_12_cm01cel02,FD_15_cm01cel02,FD_13_cm01cel02,
FD_09_cm01cel02
cm01cel03: cm01cel03_FLASHCACHE 364.75G
FD_02_cm01cel03,FD_15_cm01cel03,FD_04_cm01cel03,FD_07_cm01cel03,FD_13_cm01cel03,
FD_05_cm01cel03,FD_01_cm01cel03,FD_06_cm01cel03,FD_00_cm01cel03,FD_09_cm01cel03,
FD_11_cm01cel03,FD_10_cm01cel03,FD_03_cm01cel03,FD_12_cm01cel03,FD_08_cm01cel03,
FD_14_cm01cel03
[oracle@cm01dbm01 ~]$

2. In the output above, you can see that flash cache is enabled on each storage cell with a

capacity of 364.75 GB. Next, drop your flash cache using the cellcli command below:

[oracle@cm01dbm01 ~]$ dcli -g ./cell_group cellcli -e drop flashcache all
cm01cel01: Flash cache cm01cel01_FLASHCACHE successfully dropped