Oracle uses bare devices to store data

Under normal circumstances to write data to the table first through the library, the library to tell the operating system, the operating system to find the disk, after 3 steps!

Table----> Libraries----> Operating systems----> disks

Bare devices do not have a file system, at the system level can not control the disk, this is the bare device.

Bare equipment directly to the library, I will save data, data, library and disk direct interaction, not through the system layer, less a layer of patrol, can improve speed.

We ext3 the default block 4 K, the database of the default block 8 block, the data will certainly be stored in the disk, if the system layer must be 4K saved, need to convert it, relatively more troublesome.

The benefits of the bare device, skip the operating system layer directly to find the disk, the system layer has not recognized the disk, it uses the disk as a file "This file can not be stored directly, to Oracle use"

When you install Oracle, you can use 3 types of storage:

1. File system

2. Bare Equipment

3. ASM

Benefits of using bare devices

Since the use of bare devices avoids the layer of the operating system, the data is transferred directly from disk to Oracle,

Therefore, using bare devices can greatly improve the performance of database system for read-write database applications.

Of course, this is a very large disk I/O, disk I/O is already known as a system bottleneck in the case of the establishment.

If disk reads and writes are so frequent that disk reads and writes become a system bottleneck,

Then the use of bare equipment can greatly improve performance, the maximum can even increase to 40%, very obvious.

"10.0. Version 2.3 only started to support bare devices "

Power off, add a piece of disk

[[email protected] ~]# fdisk-l "View disk Partition"

[[email protected] ~]# fdisk/dev/sdb "N P 1 return car +100m w"

[[email protected] ~]# fdisk/dev/sdb "N P 2 return car +100m w"

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Create PV, create VG

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Create LV

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binding, Authorization, querying

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Using Bare devices in Oracle

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Note

Archived logs cannot be placed on bare devices and can only be placed on the file system or on tape

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This article is from "Allen Lee Oracle" blog, please make sure to keep this source http://lipengfei666666.blog.51cto.com/6384154/1657500

Oracle uses bare devices to store data