Please refer to the following textbook: Distributed and Cloud Computing 1st edit

Question

Please refer to the following textbook:

Distributed and Cloud Computing 1st edition

From Parallel Processing to the Internet of Things

ISBN:

0123858801

ISBN-13:

9780123858801

Authors:Kai Hwang Jack Dongarra Geoffrey Fox Geoffrey C Fox

Problem 4.5 Consider two cloud service systems: Google File System and Amazon S3. Explain how they achieve their design goals to secure data integrity and to maintain data consistency while facing the problems of hardware failure, especially concurrent hardware failures.

Explanation / Answer

Google file system and Amazon simple storage service (s3) are the distributed file system which is used for clould computing. They both are designed for high fault tolerance and data integrity.

Google file system divides it data into 64MB chunks and again it is divided into 64KB block for checksum. Google file system divides it storage into master and chunk server. Master server holds the metadata of the file system whereas chunk server hold the data blocks. Google file system maintains the replica of the data blocks for concurrent hardware failure in the chunk server. It maintains three copies of the replica, so when one or two fails it can recover the data from the third replica thus maintaining the data integigrity in case of hardware failure. It maintains a checksum for the data blocks. Checksum are the fingerprint of the data block. So in case of hardware failure it can recognize the datablock from other chunk server and send it to the client. And if master server fails it also maintains a shadow master server which is a replica of the main master server.

Amazon S3 is using a simple web service to maintains it data. Amazon S3 use buckets for its storage of data. It stores the data as a object into bucket. Amazon S3 replicates its data for data integrity ans also uses a checksum for the data. Amazon S3 uses a checksum for the data , if it finds their is a corruption in data it immediatly recovers from the other replicas. So in case of hardware failure the data is alsways consistent becaose one good copy is laways available.

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.