Quantum
Modes of the DXi on 1.X Leg of Firmware

Overview

Modes of the DXi on 1.X Leg of Firmware:

  

 

 

Detail

Normal->Truncate->Throttle->no_space->stop_io

 

  

A) Filesystem Completely Empty.

 

B) BELOW Truncation Threshold: 
- In this region, all I/O operations (to QBFS) should be allowed, without throttling.
- Deduplication should be performed according to policy and backup windows.
- No truncation should be performed.
FYI - Truncation is completely normal and should occur several times a day once the system reaches a mature state and the customer starts deleting data on a regular basis.
 
C) BELOW Throttle Threshold
- In this region, all I/O operations (to QBFS) should be allowed, without throttling.
- Deduplication should be performed according to policy and backup windows.
- Truncation should be performed as appropriate.
 
D) BELOW Critical Low Space Threshold
- In this region, write operations (to QBFS) should be throttled; read operations should not be delayed.
- Deduplication should be performed without regard to policy or backup windows.
- Truncation should be performed as possible.
 
E) BELOW Stop I/O Threshold
- In this region, no write operations (to QBFS) should be accepted.
- Deduplication should be performed without regard to backup window.
- Truncation should be performed as possible.
 
F) BELOW Filesystem Completely Full
- In this region, no I/O operations (to QBFS) should be accepted.
- Deduplication should stop.
- Truncation should be performed as appropriate.
- Getting out of this region may require manual intervention – removal of VTCs and/or NAS files

   

 

Truncation 

 

The truncation value is set via the LowWaterMarkPercent parameter.

 

On a Galaxy system, the states/modes are persistently stored in - /data/hurricane/conf/SpaceManagerStateMachine.conf

  

 [root@DXi-B1 ~]# cat /data/hurricane/conf/SpaceManagerStateMachine.conf

<?xml version="1.0"?>

<root>

<PersistentStateMachine>

<NormalState>true</NormalState>

<TruncateState>false</TruncateState>

<ThrottleState>false</ThrottleState>

<NospaceState>false</NospaceState>

<StopIOState>false</StopIOState>

<IngestThrottleStartTime>-1</IngestThrottleStartTime>

</PersistentStateMachine>

<SpaceManagementAlgorithm>

<HighWaterMarkGB>500</HighWaterMarkGB>

<LowWaterMarkPercent>70</LowWaterMarkPercent>

<HysteresisPercent>5</HysteresisPercent>

<CriticalLowSpaceGB>250</CriticalLowSpaceGB>

<StopIOGB>10</StopIOGB>

<NormalPollInterval>15</NormalPollInterval>

<ThrottlePollInterval>7</ThrottlePollInterval>

</SpaceManagementAlgorithm>

</root>

 

** Please keep in mind that water mark values above can be different depending on DXi model.

 

 

 

Throttle Mode

Throttle Mode Percentage is determined via an algorithm on the DXi and is not present as value in the SpaceManagerStateMachine.conf file.

Example:

The System enters throttle mode at roughly 95% of disk usage. The actual threshold is dependent on the total capacity of the system and is calculated as follows: 500 GB (Base) + 100 GB additional per every 10 TB capacity.  Throttling threshold = 800 GB on 32 TB system, 1.7 TB on 129 TB system, 500 GB on 5.4 TB system In this state - the ingest is throttled by QBFS to catch up on dedup and truncate. The backup window policies are overridden. Unrealized VTL carts would be truncated as well. Throttle delay starts at 16 ms and is doubled every 1 minute and attains maximum of 1024 ms. In this mode BPGC is automatically triggered regardless of current Space Reclamation schedule.

  

 

 

Additional Resources

 


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