Databases Reference
In-Depth Information
How It Works
The RECO diskgroup is a special diskgroup that is usually created during the initial installation and configuration
of Exadata—a task normally undertaken by the Oracle Advanced Customer Service staff, but occasionally by the
customer or a third party as well. The diskgroup is created by using the griddisks closer to the center of the disk, which
are usually slower compared to the griddisks created by areas near the periphery of the disk.
When you use a fast recovery area, RMAN automatically puts the backup files there. Therefore, you don't have to
mention the location explicitly. When you use a diskgroup not defined as an FRA, you have to use that in the format
clause of the
allocate channel
command.
Backing Up Outside the Exadata Rack
Problem
You want to back up the database on Exadata to a location outside the Exadata rack.
Solution
Three solutions are possible. The first two involve treating an external disk as an FRA. Your choice comes down to
whether that external disk is in the form of an ASM diskgroup, or in the form of an NFS mount point. Your third option
is to back up to an NFS mount point that you do not configure as an external FRA.
Option A: Using an External ASM Disk Group as an FRA
This solution is very similar to that in Recipe 24-2. The only difference is that the storage comes from the outside.
Here are the general steps:
1.
Identify the location of external storage. This could be a general-purpose network attached
storage device connected via some network transport mechanism, such as Infiniband
(preferred due to its high throughput and low latency), or 10 Gbps Ethernet, which is more
versatile. This location is visible to the Compute Nodes.
2.
Make sure the network is configured for jumbo frames.
3.
Logging in as the Grid Infrastructure owner on the Node, and create the diskgroup.
4.
Referring to Recipe 24-2, issue the following commands shown in step 9 for creating the
fast recovery area.
5.
Referring to Recipe 24-3, follow the rest of the steps from step 10 and beyond.
Option B: Using an External NFS Mount Point as an FRA
This is exactly the same as the previous option, except that the location is not an ASM diskgroup but a mount point.
Referring to Recipe 24-2, replace steps 1 through 8 as follows:
1.
Mount a file system on a NAS location. Let's assume it is called /oraback. Confirm its
presence by issuing the following command:
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VGExaDb-LVDbSys1
30G 19G 9.8G 66% /
