Three copies, two kinds of storage, one off site. It is an old rule of thumb, and it still maps neatly onto how a small business should protect its data.
The 3-2-1 idea has been around for decades and it survives because it is easy to remember and hard to argue with. It is a guideline for arranging copies, not a product or a compliance requirement.
The live data counts as one. So a business with a server and one backup has two copies — which is better than most, and still one bad coincidence away from nothing. The third copy covers the case where a restore fails or a backup turns out to be incomplete.
Copies on the same kind of device tend to fail the same way. A server and a NAS, or a NAS and cloud storage, are more independent than two volumes inside the same chassis. In practice this usually means: production storage plus backup storage of a different sort.
This is the part people postpone, and the part that matters when something physical happens. Fire, theft, water and electrical damage do not care how well the RAID is configured. Off site can be cloud storage, a backup at another branch, or a rotated disk kept somewhere safe.
Cloud is usually the least trouble, because it needs no one to remember anything. Rotated disks work perfectly well too, as long as somebody genuinely rotates them — in practice that needs a named person and a habit, not an intention.
Retention is the other half of the design, and the half that is usually skipped. Daily copies kept for two to four weeks handle the common case: something broke last night. Monthly copies kept for a year handle the slower discoveries — a ledger that has been wrong since March, a folder nobody opened until the audit. If every copy is overwritten within a week, you are protected against hardware failure but not against mistakes.
If your current setup misses two or three of these, that is normal — and fixable in an afternoon for most small offices.
A NAS keeps your files in one reliable place. That is storage, not backup — and the difference only becomes obvious on the day you need to recover something.
Read article : Is a NAS a backup? What business owners need to knowAccounting data is the least replaceable thing most businesses own. Here is a practical way to plan its backup, including the parts specific to Tally and similar applications.
Read article : How to plan backup for Tally and other business dataBoth run your servers as virtual machines. The real decision is about licensing, in-house skills, support expectations and what your applications need.
Read article : Proxmox or VMware: what a small business should considerWe'll look at what you have, explain the practical options and tell you what we would do.