Disaster Recovery Technology for Google cloud computing

Disaster recovery is an unpleasant topic, but it must be addressed. Taking a company's email system as an example, some companies will back up past emails, probably every day or every week, after a disaster,
Although the backup data can be restored to the system, this periodic backup only ensures the security of the backup data. The data between the last backup and the disaster is completely lost.

 

In large companies, San may be used for backup, which is very expensive. In addition, when the entire data center fails
No insurance. Therefore, large companies with real strength will create a new data center in different regions and create a complete set of remote backup.

However, the sky is often unsatisfactory. Sometimes, even two data centers in two locations will crash at the same time. Therefore, more powerful companies will make the physical distance between the two data centers as much as possible (the farther it means
The higher the cost), but it brings about management problems. The transmission of terabytes of data between two San sets requires a very high bandwidth. In any case, this is related to the cost, the more redundancy, the higher the cost.

Disaster backup and recovery have two indicators: RPO (rediscovery
Point Objective
), One is RTO (recovery
Time Objective
), That is, the data loss rate and the recovery interval. For traditional SAN
Or remote backup, these two indicators basically depend on the cost, the better the indicator, the higher the cost, Google in this regard, the use of synchronous replication technology, synchronous replication so that RPO close to 0, and
RTO is close to real-time, that is, when a disaster occurs, data loss of all Google online applications is basically 0, and the recovery interval is close to real-time, so that users are completely unaware of it (however, Gmail
How many times of downtime is going on?-translator ). The data synchronization replication technology is applied to all Google online applications (including Gmail, Google
Calendar AR, Google Docs, and Google sites). All the data you need to save is synchronized to Google
When any data center fails, the system immediately switches to another data center.

The operation cost of synchronous replication backup is quite high. In the commercial storage field, the 25 GB synchronous storage service may need between 150 to more than 500 USD per year.
You can use the following methods to ensure that these high-cost technologies are free of charge:

1. One Google Data Center supports millions of users. Therefore, the cost shared by each user is much lower.
2. Google's standby data center is not enabled in the event of a disaster, but is still in use. Google is always balancing these data centers to ensure no waste of resources.
3. Google's data centers have their own highly connected networks to ensure fast data transmission.

 

The advantage of cloud computing is the rapid popularization of advanced technologies.
Cloud computing, cloud storage and other applications, so that those previously only super companies have the ability to enjoy services become very common, and the cost is very low.

Source: http://googleenterprise.blogspot.com/2010/03/disaster-recovery-
By-google.html, delivered by Rajen sheth, Google Apps Senior Product Manager

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