PowerStore: Trickle Write Mode
Summary: Trickle Write mode is introduced with PowerStoreOS 4.0. It is intended to preserve drives, avoid scenarios where multiple drives fail simultaneously, and force proactive drive replacement. ...
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Instructions
Trickle Write mode
The DataPath in PowerStore is designed to wear drives evenly. As an appliance ages, it is likely for multiple drives to wear out around the same time.
PowerStore Data Protection controls the rebuild process when drives are replaced. If multiple drives fail simultaneously, rebuild cannot work correctly and data loss can occur.
Trickle Write mode:
• Disables background services, such as space reclamation
• Stops I/O to all drives
• Transitions NAS to read-only mode
• Triggers a red banner in PowerStore Manager and generates critical alerts
A system is placed in Trickle Write mode when the fault tolerance plus one drive reaches 99% worn.
For example:
- Clusters set to Single Drive Failure enter Trickle Write mode when two or more drives reach End of Life.
- Clusters set to Double Drive Failure enter Trickle Write mode when three or more drives reach End of Life.
Tip: PowerStore Manager calls the feature a guardrail, while the service command references wear_trickle_write.
Complete the recovery process (svc_wear_trickle_write)
This service script enables you to complete the manual recovery process once the system enters wear trickle write mode.
Usage
| Function | System Operations |
| Mode | Service |
| Usage | Service |
| Requires service user password? | Yes |
| Requires root privileges? | Yes |
| May cause data unavailability? | Yes |
| May cause data loss? | No |
| Scope | Node |
| Prerequisites | None |
Format
svc_wear_trickle_write [-h] {exit_trickle,enable_policy,show_drives,list_policy}
Optional arguments
| QUALIFIER | DESCRIPTION |
|---|---|
| -h, --help | Show the help message and exit. |
Actions
| ACTION | DESCRIPTION |
|---|---|
| exit_trickle | Manually exit wear trickle write mode. Use this command after the recovery procedure is complete. If you want to continue using the worn-out drives and exit trickle write mode, you must disable the exit trickle write policy before using this command. |
| enable_policy | Enable wear the trickle-write policy. The wear trickle-write policy is enabled by default. |
| show_drives | List all worn-out SSD drives in the system. |
| list_policy | Get the current wear trickle-write policy setting. |
| disable_policy | Disable the wear trickle-write policy. |
Dell PowerStore Service Scripts Guide
https://dl.dell.com/content/manual61302475-dell-powerstore-service-scripts-guide.pdf?language=en-us
Affected Products
PowerStore, PowerStore 1000T, PowerStore 1200T, PowerStore 3000T, PowerStore 3200T, PowerStore 5000T, PowerStore 500T, PowerStore 9000T, PowerStore 9200TArticle Properties
Article Number: 000226721
Article Type: How To
Last Modified: 09 Jul 2024
Version: 1
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