---
title: "Troubleshooting & FAQ"
description: "Common issues and frequently asked questions about PFS"
---

# Troubleshooting & FAQ

## Common Issues

### Issue: Unable to Mount PFS

**Symptoms:** PFS fails to mount on compute instance

**Possible Causes & Solutions:**
1. **PFS not unmounted from previous resize:** Complete any pending operations
2. **Incorrect mount path:** Ensure mount path is valid and doesn't conflict with existing directories
3. **PFS in error state:** Check status in dashboard and contact support

### Issue: Resize Operation Failed

**Symptoms:** Resize doesn't complete or PFS enters error state

**Possible Causes & Solutions:**
1. **PFS still mounted:** Ensure PFS is completely unmounted from all Instances before resizing
2. **Active I/O operations:** Wait for all operations to complete
3. **Backend issue:** Contact support with error details

<br/>

:::warning Critical Step
Always unmount PFS from **all** attached Instances before attempting to resize. Failure to do so will cause the resize operation to fail.
:::

### Issue: Poor Performance

**Symptoms:** I/O operations slower than expected

**Possible Causes & Solutions:**
1. **Network bottleneck:** Verify network bandwidth and latency
2. **Suboptimal access patterns:** Review and optimize I/O patterns
3. **Resource contention:** Check if compute nodes have sufficient resources
4. **Wrong performance tier:** You may need a higher performance tier
5. **Too many concurrent operations:** Optimize application parallelism

### Issue: Cannot Delete PFS

**Symptoms:** Deletion operation fails or is unavailable

**Possible Causes & Solutions:**
1. **PFS still mounted:** Unmount from all attached Instances first
2. **Active services using PFS:** Stop all services accessing the PFS
3. **Pending operations:** Wait for any resize or maintenance operations to complete


## Frequently Asked Questions

### General Questions

**Q: What makes PFS different from SFS?**  
A: PFS is optimized for high-performance parallel I/O workloads, offering superior throughput and IOPS compared to SFS. It's designed for HPC applications and intensive multi-node training scenarios.

**Q: Can I convert an existing SFS to PFS?**  
A: No, you cannot directly convert SFS to PFS. You would need to create a new PFS and migrate your data.

**Q: How many Instances can access a PFS simultaneously?**  
A: PFS is designed for high-concurrency parallel access. The exact number depends on your configuration and performance tier.

### Mounting & Access

**Q: Why must I unmount PFS before resizing?**  
A: Unmounting ensures data consistency and prevents corruption during the resize operation. Active I/O during resize can lead to data loss.

**Q: Can I specify custom mount paths?**  
A: Yes, you can specify your preferred mount path when attaching PFS to compute instances, allowing flexible integration with your applications.

**Q: What happens to data when I unmount PFS?**  
A: Data remains intact on the PFS. Unmounting only disconnects the file system from that specific node. You can remount it later without data loss.

**Q: Can I mount the same PFS to Instances in different regions?**  
A: No, PFS is region-specific. Instances must be in the same region as the PFS for optimal performance.

### Performance

**Q: How do I know if I need PFS instead of SFS?**  
A: Consider PFS if you:
- Require maximum I/O throughput
- Run HPC or parallel computing workloads
- Need consistent high performance under heavy concurrent access
- Have budget for premium storage

**Q: Why is my PFS not performing as expected?**  
A: Check:
- Network bandwidth between nodes and storage
- I/O access patterns (sequential vs random)
- Number of concurrent operations
- Node configuration and resources

**Q: What throughput can I expect from PFS?**  
A: Performance varies based on your specific configuration and workload.


### Data Management

**Q: How do I backup PFS data?**  
A: Implement regular backups by:
- Copying data to Datasets (EOS) for long-term archival
- Using rsync or parallel copy tools for large datasets

**Q: What happens if I delete PFS by accident?**  
A: Data deletion is permanent and cannot be recovered. Always maintain backups and follow the deletion confirmation process carefully.


## Data Safety Recommendations

### Backup Strategy

:::danger Critical Reminder
PFS deletion is permanent and irreversible. Always maintain backups of mission-critical data.
:::

**Recommended Approach:**
1. **Automated Backups:** Schedule regular backups to external storage
2. **Datasets Integration:** Archive important data to Datasets (EOS)
3. **Version Control:** Use appropriate tools for code and configuration
4. **Disaster Recovery:** Maintain copies in different regions for critical data

### Before Resizing

:::warning Pre-Resize Checklist
1. **Unmount from all Instances** - Verify no Instances have PFS mounted
2. **Backup critical data** - Create backups as additional safety measure
3. **Stop dependent services** - Ensure no applications are accessing PFS
4. **Verify requirements** - Confirm new size meets your needs
:::

### Before Deletion

:::danger Pre-Deletion Checklist
1. **Verify backups** - Confirm all important data is backed up elsewhere
2. **Check dependencies** - Ensure no active workloads depend on this PFS
3. **Unmount completely** - Remove PFS from all attached Instances
4. **Double-check PFS ID** - Verify you're deleting the correct file system
:::


## Security Best Practices

*   **Access Control:** Limit PFS access to only necessary compute instances
*   **Data Sensitivity:** Understand compliance requirements for stored data
*   **Regular Audits:** Review which Instances have access to each PFS
*   **Unmount When Idle:** Unmount PFS from Instances that aren't actively using it


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