Choosing a VM size
Overview
SFTP Gateway is an Azure marketplace machine image, and charges a software fee on top of the price of the VM.
When choosing a VM size, you want to balance price and performance. This article gives a general overview of the VM sizes you might want to consider.
VM Series
In general, you'll be looking at series B, D, or E. See this page for details.
- B series: This stands for "burst". The baseline performance is really low, but it can "burst" up to decent performance for short periods of time. This is ideal for something that sits idle all day, and handles light traffic when it does get used.
- D series: This has good baseline performance, and is the first series rated for Production use.
- E series: Memory-optimized VMs designed for in-memory applications, with a high memory-to-CPU ratio.
Note: Azure A series VMs are not available in the current generation.
There are also additional letters and numbers after the initial "series" letter. These refer to various versions, or modifications to memory and compute.
Recommended VM instance sizes
The following table shows current VM instance options with their specifications and Linux on-demand pricing:
| VM Instance Size | vCPUs | Memory (GiB) | Linux On-Demand ($/Hour) |
|---|---|---|---|
| Standard_B1ms | 1 | 2 | $0.0207 |
| Standard_B2s | 2 | 4 | $0.0416 |
| Standard_D2s_v4 | 2 | 8 | $0.0960 |
| Standard_D4as_v4 | 4 | 16 | $0.1920 |
| Standard_D8s_v4 | 8 | 32 | $0.3840 |
| Standard_E2as_v4 | 2 | 16 | $0.1260 |
When testing SFTP Gateway in a demo or dev environment, the most cost-effective option is a Standard_B1ms at $0.0207 per hour. This VM size has 1 vCPU and 2 GB of RAM. It's burstable, which means you're only paying a fraction of what it would normally cost for this level of baseline performance.
For development environments that need slightly more consistent performance, consider the Standard_B2s at $0.0416 per hour, which provides 2 vCPUs and 4 GB of RAM while still maintaining burst capabilities.
When you are ready to go to production, you should consider using at least a Standard_D2s_v4 at $0.0960 per hour. This VM size has 2 vCPUs and 8 GB of RAM. This is a production-grade VM size that can handle sustained traffic without burst limitations.
For higher-performance production workloads, Standard_D4as_v4 ($0.1920 per hour) provides 4 vCPUs and 16 GB of RAM for moderate to heavy workloads, while Standard_D8s_v4 ($0.3840 per hour) offers 8 vCPUs and 32 GB of RAM for high-performance requirements.
If your SFTP Gateway handles memory-intensive operations or large file processing, consider the Standard_E2as_v4 at $0.1260 per hour. This provides 2 vCPUs with 16 GB of RAM, offering a high memory-to-CPU ratio that's ideal for applications requiring significant memory resources.
If you are going to production but your workload is very small (i.e., just a few users sending files once a month), the Standard_B1ms or Standard_B2s might still be suitable, as long as you understand the burst credit model and your usage patterns don't exceed the baseline performance for extended periods.
Here is a helpful online tool when searching for VM pricing and comparisons.
Note: Pricing shown is for Linux on-demand instances and may vary by region. Check Azure pricing calculator for the most current rates in your specific region.