That very much depends on how busy yo expect your system to be used.
If you will only have 8 to 10 users and a small amount of transactions throughout the day, then any linx VPS srver with at least 2 virtual CPU and 4gb of memory or more would likely be just fine.
However, if you will have several POS terminals, and dozens of stock transfers taking place throughout the day hen I would consider increasing the server size to at least 4 virtual CPU and 16gb of memory.
There is one point though that most people do not consider, and that is the quality of the VPS server company you choose to use for your public facing system. Some suppliers of VPS services grossly over-sell their system and try to host to many separate VPS instances on their hardware. Or they allow gamin hosts to hog much of the bandwidth of a server leaving not much processor ability for the others to use.
It is important to check the user feedback on any company you consider for your hosting provider. They vary greatly from location to location. Much of it will depend on what services are closest to your user base. I tend to use hosting providers with server farms no more than 300 miles from my user location and then setup backup servers in cities more than 900 miles away to use in the event of a catastrophic failure of my primary server.
Things to consider:
- How busy will my system be?
- What times of day will there be peak activity?
- How critical will server access be? (will business stop if access is cut)
- If I lose my system completely, how will this affect the business?
- How much time can I operate a business without access to my system?
- Is the internet service provider stable enough in my location?
- Can I afford the cost of a “better” VPS service provider or can I only afford a cheap one?
- What are my linux server abilities? (do I need a “managed” server or can I do it myself)
- Can I afford to run multiple servers so that I have a hot spare backup?
The self evaluation process is never really that hard, but there is a lot to consider.
I am NOT a great server wizard, but I can get by maintaining them myself. I have a user base that would have business grind to a complete halt if the server became unavailable for any reason, so that plays an important role in my decision making.
I run multiple servers for my users. One is a primary live production server and the other two are “hot spares” that receive copies of the database backup from the primary production server every hour during the busiest part of the working day. That way I can do a restore on one of the backups if the primary server dies or is cut off from the internet and have my users all switch to the backup server. Once I get the primary server fixed or replaced, I have them switch back. This has saved me several times over the past 6 years.
Here is a tutorial on how I set this up: (just in case you need it)
If you just want to experiment with VPS servers until you find your balance with keeping a live system running, you might try using some of the deals available at lowendbox.com
They list the cheap deals on small vps servers that are promotional sales from all different vendors all over the world. I have used many of their offerings to teach myself the pitfalls and successes of running ERPNExt on different kinds of VPS providers.
Once you have figured out your tolerance for “inconvenience” and what you are willing to live with, it become easier to pick a path and jump right in.
Good luck on your ERPNext adventure.
BKM