---
title: "VAST Probe Requirements"
slug: "vast-probe-requirements"
description: "VAST Probe: Discover essential hardware & software reqs for smooth performance and robust scanning capabilities."
updated: 2026-11-03T18:27:48Z
published: 2026-11-03T18:27:48Z
canonical: "docs.vastdata.com/vast-probe-requirements"
---

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

# VAST Probe Requirements

## Audience

This guide helps you understand the Probe hardware and software requirements. This is intended for customers who are running the Probe on their own infrastructure. You can learn how to quickly run the Probe by following the instructions in [VAST Probe Quickstart](/kb/docs/vast-probe-quickstart).

## Hardware Minimum Requirements

Actual hardware requirements depend on the amount of data to be scanned. Examples of how to scope hardware based on dataset size are provided at the end of this page.

- **16** **CPU cores** or higher Intel **Broadwell-compatible** or later CPUs.
  - The Probe requires CPU instructions that are not available on older CPUs.
  - The Probe will run virtually on Intel-based hardware with a Virtual Cluster vMotion minimum compatibility of Intel Broadwell or later.
  - The Probe has not been evaluated on AMD CPUs.
- **128 GB RAM** or higher
  - The probe consumes almost 100GB of RAM upon launch.
  - The more RAM, the better the Probe will perform and the more data it can scan.
- **10 GbE** **Networking** or higher
- **50 GB** **SSD-backed local storage** or higher (NVMe or FC/iSCSI LUNs).
  - This local SSD capacity is needed for the database the probe builds and logging.
  - Must be equivalent to 0.6% of the data to be scanned.
  - Disk storage must have very high sustained IOPs.
  - The larger the local SSD allocated, the more data you can scan.
  - Local SSD filesystem should be ext4 or XFS.

## Operating System Minimum Requirements

We've tested the following, but most modern Linux distributions should be fine:

- Ubuntu 18.04, 20.04
- CentOS/RHEL 7.4+
- Rocky/RHEL 8.3+

## Software Requirements

- Docker: 17.05 +
- python3 (for launching the Probe)
- screen (for running the Probe in the background)
- wget (for downloading the Probe image)

## Filesystem Requirements (For Probing For Data Reduction)

Be aware that if the filesystem has **atime** **enabled**, any scanning, even while mounted as read-only, will update the atime clock.

- **NFS:** The Probe host has been provided **root-squash** and **read-only** access
  - For faster scanning, use an operating system that has [nconnect](https://medium.com/@emilypotyraj/use-nconnect-to-effortlessly-increase-nfs-performance-4ceb46c64089) support:
    - Ubuntu 20.04+
    - RHEL/Rocky 8.4+
- **Lustre**: The Probe host and container must be able to **read as a root** user
- **GPFS**: The Probe host and container must be able to **read as a root** user
- **SMB**: The Probe host should be mounted with a user in the **BUILTIN\Backup Operators** group to avoid file access issues.
- **S3/Object**: We have tested internally with [Goofys](https://github.com/kahing/goofys) as a method of imitating a filesystem
  - It is not recommended to scan anything in AWS Glacier or equivalent

## Hardware Requirement Examples

**Example A**: You have a server with **768GB of RAM**:

- **154GB** is for the Operating System, leaving **614GB of RAM**...
- There are 100 million files to scan, which will occupy **~5GB of RAM**, leaving **609GB of RAM**...
  - 50 bytes per 'filename'.
- This leaves **609GB of RAM** available for the **RAM index.**
  - ```plaintext
--ram-index-size-gb 609
```
  - This can **scan up to 99TB of data** using only RAM, with no significant local SSD space required.
    - This calculation uses a 0.6% rule to accommodate similarity and deduplication hashes.
- Using a disk index, you can scan far more data, and the file count could exceed 10 billion with a 500GB file name cache.

**Example B**: You have a server with **128GB of RAM** and a **Local SSD**:

- **26GB** is for the Operating System, leaving 102GB of RAM...
- There are 100 million files to scan, which will occupy **~5GB of RAM**, leaving **97GB of RAM**...
  - 50 bytes per 'filename'.
- This leaves **97GB of RAM** available for the **RAM index**
  - ```plaintext
--ram-index-size-gb 97
```
  - This can **scan up to 15TB of data** using only RAM, with no significant local SSD space required.
    - This calculation is based on a 0.6% rule to accommodate similarity and deduplication hashes.
- Using a disk index, you can scan far more data, and the file count could be as high as 2 billion, with a 100GB file name cache.
  - 15TB of data requires 90GB of local SSD disk.
  - 100TB of data requires 600GB of local SSD disk.

## Algorithm Specification

Here's pseudo-code that helps to explain how these calculations are done:

```plaintext
available_ram_bytes = (avail_b * 0.8) - (n_files * 50)
 ram_index_size = args.ram_index_size_gb * GB
 disk_index_size = args.disk_index_size_gb * GB
 if disk_index_size == 0:
 if ram_index_size == 0 and available_ram_bytes > index_size:
 ram_index_size = index_size
 if ram_index_size == 0:
 disk_index_size = index_size
 if 0 < ram_index_size < GB:
 ram_index_size = GB
 if 0 < disk_index_size < GB:
 disk_index_size = GB
```