<p>No. You need the rev*.dat files as much as you need the blk*.dat files. If Bitcoin Core cannot find the rev*.dat, it will need to regenerate them by reindexing the databases. Removing them effectively corrupts the databases.</p>

<p>If you want to save disk space, you can use pruning instead. This will have Bitcoin Core properly remove blk*.dat and rev*.dat files to save disk space.</p>

CC BY-SA 3.0
2018-02-23T14:32:56.453Z
I don't want to prune. I need a full node. Did you actually test what you are saying? In which occasion the node will recognize some rev files are missing? I am asking because I stopped the node, moved some old rev files and restarted the node. There is no error message in the log neither the regenerated files
Riccardo Casatta
CC BY-SA 3.0
2018-02-23T16:02:27.277Z
A pruned node is still a full node. I have done this in the past and it resulted in a reindex. It looks like Bitcoin Core doesn't verify the undo data as much as it does for the block data, but it still does some verification. If you delete the wrong files, it will have problems.
Ava Chow
CC BY-SA 3.0
2018-02-24T18:41:01.463Z
yeah sorry for the wrong terminology, anyway I want all the blockchain data. I still suppose the wrong files causing problems are only the recent rev* files. I would like to see other answer
Riccardo Casatta
CC BY-SA 4.0
2018-05-23T16:12:11.240Z
I can now confirm after testing my node started to recreate rev files in a very long process after I deleted it. So somehow are needed also the old ones
Riccardo Casatta
CC BY-SA 3.0
2018-02-23T03:40:25.980Z
2018-02-23T03:40:25.980Z
Ava Chow
<p>based on this <a href="https://bitcoin.stackexchange.com/a/32723/6693">answer</a> rev files contains information for dealing with reorgs.
If I think reorg longer than let's say a month are highly unlikely, could I safely delete rev*.dat files older than a month?</p>

CC BY-SA 4.0
2018-05-19T11:02:49.093Z
Why not to test deleting rev*.dat files in `testnet` environment and check? :)
amaclin
<bitcoin-core><blockchain><chain-reorganization><undofiles>
Are old rev*.dat file safely deletable?
Riccardo Casatta
# Are old rev*.dat file safely deletable?

(Asked by: username_0 on 2018-02-22)

based on this [answer](https://bitcoin.stackexchange.com/a/32723/6693) rev files contains information for dealing with reorgs.
If I think reorg longer than let's say a month are highly unlikely, could I safely delete rev\*.dat files older than a month?

**Tags:** bitcoin-core, blockchain, chain-reorganization, undofiles

> **Comments:**
> **username_1**: Why not to test deleting rev*.dat files in `testnet` environment and check? :)  

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## 1 answers

### Answer by username_2 on 2018-02-23. Score: 3 | Accepted answer

No. You need the rev\*.dat files as much as you need the blk\*.dat files. If Bitcoin Core cannot find the rev\*.dat, it will need to regenerate them by reindexing the databases. Removing them effectively corrupts the databases.

If you want to save disk space, you can use pruning instead. This will have Bitcoin Core properly remove blk\*.dat and rev\*.dat files to save disk space.

> **Comments:**
> **username_0**: I don't want to prune. I need a full node. Did you actually test what you are saying? In which occasion the node will recognize some rev files are missing? I am asking because I stopped the node, moved some old rev files and restarted the node. There is no error message in the log neither the regenerated files  
> **username_2**: A pruned node is still a full node. I have done this in the past and it resulted in a reindex. It looks like Bitcoin Core doesn't verify the undo data as much as it does for the block data, but it still does some verification. If you delete the wrong files, it will have problems.  
> **username_0**: yeah sorry for the wrong terminology, anyway I want all the blockchain data. I still suppose the wrong files causing problems are only the recent rev* files. I would like to see other answer  
> **username_0**: I can now confirm after testing my node started to recreate rev files in a very long process after I deleted it. So somehow are needed also the old ones  

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