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In centos7, uuid is a universal unique identifier and a standard for software construction. The function of uuid is to allow all elements in the distributed system to have unique identification information without having to pass The central control terminal performs the designation of identification information.
The operating environment of this article: centos 7 system, Dell G3 computer.
Introduction
UUID means universal unique identification code. This is a standard for software construction and is also open source The Software Foundation's organization is part of the field of distributed computing environments.
Function
The purpose of UUID is to allow all elements in the distributed system to have unique identification information without the need for a central control end. Designation of identifying information. This way, everyone can create UUIDs that don't conflict with anyone else's. In this case, there is no need to consider the duplication of names when creating the database.
Composition
UUID refers to a number generated on one machine, which is guaranteed to be unique to all machines in the same time and space. Usually the platform will provide a generated API. Calculations based on standards set by the Open Software Foundation (OSF) use the Ethernet card address, nanosecond time, chip ID and many possible numbers.
UUID is a combination of the following parts:
(1) Current date and time, the first part of UUID is related to time, if you generate a UUID, after a few seconds it will To generate a UUID, the first part is different and the rest are the same.
(2) Clock sequence.
(3) Globally unique IEEE machine identification number. If there is a network card, it is obtained from the MAC address of the network card. If there is no network card, it is obtained by other means.
The standard UUID format is: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxx
(8-4-4-4-12). You can download CreateGUID() UDF from cflib for conversion.
View hard disk UUID
Method one:
ls -l /dev/disk/by-uuid
Method two:
blkid /dev/sda5
Recommended tutorial: "centos tutorial"
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