NXT 1.7.4 just released a new Data Cloud feature:
- How long do files last on the NXT blockchain?
Files and any other prunable data are maintained by all nodes for 90 days by default (controlled by nxt.maxPrunableLifetime in nxt-default.properties). The minimum value is 14 days on mainnet and 24 hours on testnet.
Note that pruning is performed at the same time as derived table trimming, which by default is every 1000 blocks, so the actual removal of the prunable data from the database will happen with some delay after their expiration time.
A node can choose to keep prunable data longer, by setting the nxt.maxPrunableLifetime property to a larger value. Changing this value only affects transactions received after the change. Pruning can be disabled completely by setting this property to -1.