> ## Documentation Index
> Fetch the complete documentation index at: https://docs-v2.ard.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Server startup time

> Understanding why ModMS server takes time to start and how to optimize it

Server startup can take approximately **3 minutes** due to metadata scanning.

## Root Cause

The server scans all NetCDF files at startup to build its metadata index. As the number of files increases over time, this scanning process takes longer.

**Why this happens:**

* The server needs to index all available model runs
* Metadata is extracted from each NetCDF file
* This index is used for efficient querying during runtime

## Current Limitation

Lazy loading of NetCDF files and their metadata is not currently implemented, so all files must be scanned at startup.

<Note>
  A different approach could be taken to load NetCDF files and their metadata lazily, but this is not currently implemented. This would significantly reduce startup time for large datasets.
</Note>

## Recommended Solution

When doing a cold startup, use a gradual scaling approach:

**Cold Start Strategy:**

1. **Start with minimal replicas** (recommended: 2)
2. **Wait for initialization** - Let those replicas be ready and fully initialized
3. **Scale up gradually** - Scale up to the desired number of replicas once the initial ones are operational

This approach ensures that:

* The initial load is distributed across multiple instances
* Users can access the service while additional replicas are starting
* System resources are used more efficiently
* No single point of failure during startup

## Performance Impact

**Factors affecting startup time:**

* Number of NetCDF files in storage
* File sizes and complexity
* Storage I/O performance
* Server hardware resources

**Typical startup times:**

* Small datasets (\< 1000 files): \~30 seconds
* Medium datasets (1000-10000 files): \~1-2 minutes
* Large datasets (> 10000 files): \~3-5 minutes

## Monitoring

Monitor server startup in logs to track:

* Time taken for metadata scanning
* Number of files processed
* Any errors during initialization

## Related Topics

* [Architecture Overview](/data-ai/modms/architecture)
* [Adding New Models](/data-ai/modms/faq/adding-new-model)