- How the purpose of a backup differs from an archive
- Comparing how long you keep each, how you find things, and how you delete them
- Steps for labeling each folder by purpose
The short answer
A backup is a copy you keep so you can put things back when data is damaged or deleted. An archive is where you keep material you no longer use day to day but must hold on to for a set period. Both are "saving," but the purposes differ, so the rules for how long to keep things, how to find them, and how to delete them differ too. If one folder tries to do both jobs, it often ends up doing neither well.
Both are copies, with different purposes
- A copy to restore from when something breaks or is lost
- Replaced by newer points in time
→ Check that you can restore
- Keeping what is no longer in use but must be kept
- Left unchanged for a set period
→ Check that you can find it
How they differ
| Point | Backup | Archive |
|---|---|---|
| Purpose | Put current data back | Keep finished work |
| Contents | A copy of data in use now | Originals moved out of daily use |
| How long | Older copies are replaced as new ones are made | Set by law, contracts, or internal rules |
| How you find things | By point in time | By what the record is |
| How you delete | Replace generations past the set number | Check and delete after the period ends |
A simple way to tell them apart: a backup answers "I want yesterday's version back," and an archive answers "I need the papers for that deal three years ago."
What happens when you mix them
Take a made-up example: a small office copies its data to an external drive every night and also treats that drive as the place for old records. If the backup software is set to replace older generations in turn, old files the office meant to keep can be replaced and lost without anyone noticing.
The opposite also causes trouble. If finished projects stay in the working folders, old files show up in every search, and someone may edit an outdated version by mistake. Every backup also includes all the old material, so copies grow larger and restoring takes longer.
How to separate them
- For each folder, write down whether it is "a copy to restore" or "a store to keep"
- For archives, note why you keep them and the basis for the period (law, contract, internal rule)
- Give archives names and a list that let you search by what the record is, such as project or year
- Decide who checks and deletes material once its period ends, so document disposal has an owner
- For backups, try an actual restore at least once
Some records have retention periods set by law. For example, Japan's National Tax Agency guidance on retention periods for corporate tax books and records sets out how long books and transaction documents must be kept, and the length varies by fiscal year and conditions. This article does not give the numbers, so check the official guidance from the agency responsible for each type of record. Records received as data also have their own storage rules. The tax rules mentioned here apply in Japan; elsewhere, check the rules where you operate.
Cautions
If your archive lives in only one place, losing that place means losing everything in it. Decide whether the material you must keep also needs a copy somewhere else. And if you keep everything without setting periods, you will not be able to find things, and you will end up holding data you should have deleted. Deleting data is part of the rules, just like keeping it.
If it is still not clear
For records whose retention period is unclear, check the National Tax Agency guidance or ask your tax accountant or the person in charge of administration. For how to take backups and set generations, check the official manuals for the device or software you use.
Checklist
- Did you label each folder by purpose?
- Did you note why each archive is kept and the basis for its period?
- Can you search the archive by what the record is?
- Did you decide who checks and deletes material after its period ends?
- Did you try an actual restore from your backup?
One thing to check today
Pick one folder you keep data in, and write down whether it is "a copy to restore" or "a store to keep."