Quantum 3.5 manual assume the stripe group is already in real-time mode as a, Failure Semantics

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Appendix D Quality of Service Guide

Callbacks

Figure 62 Non-Real-time

Token Adjustments

 

In Figure 62, assume the stripe group is already in real-time mode as a

 

result of an RTIO request from client A. Clients B and D are doing non-

 

real-time I/O to the stripe group and have a token that specifies the

 

amount of non-real-time I/O available. Client C then requests a non-real-

 

time I/O token in Step 1. The FSM calls back to Clients B and D and

 

specifies the new token amount in Steps 2-3. The clients respond in Steps

 

4-5, acknowledging the new token amount. The FSM then responds to

 

Client C with the new token in Step 6.

 

There are two major failures that affect QOS: FSM crashes and client

Failure Semantics

crashes. These can also be loss of communication (network outages). For

 

 

client and server failures, the system attempts to readjust itself to the pre-

 

failure state without any manual intervention.

StorNext 3.5 Installation Guide

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Quantum 3.5 manual assume the stripe group is already in real-time mode as a, Client C with the new token in Step