Fujitsu ETERNUS DX60 S3 - Chapter 3 Functions; Data Protection; Data Block Guard; Figure 3.1 Data Block Guard

Chapter 3
Functions
This chapter explains the available functions for the ETERNUS DX.
3.1 Data Protection
The ETERNUS DX has functions to securely protect user data.
3.1.1 Data Block Guard
When data is written from the server, the Data Block Guard function adds eight bytes check codes to each
block (every 512 bytes) of the data and verifies the data at multiple checkpoints to ensure data consistency.
This function can detect a data error when data is destroyed or data corruption occurs. When data is read
from the server, the check codes are confirmed and then removed, ensuring that data consistency is verified
in the whole storage system.
Figure 3.1 Data Block Guard
Cache memory
2
1
2
3
Controller
Write
A0 A1 A2
User data
A0 A1 A2
User data
CC: Check code
A0
CC
A1
CC
A2
CC
Read
Written data
A0
CC
A1
CC
A2
CC
A0
CC
A1
CC
A2
CC
1. The check codes are added
2. The check codes are confirmed
3. The check codes are confirmed and removed
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FUJITSU Storage ETERNUS DX60 S3 Disk storage system Overview
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