# Disk snapshots on FDB **URL:** \ **Category:** Running FoundationDB\ **Created:** [January 20, 2023, 8:02pm UTC](https://forums.foundationdb.org/t/disk-snapshots-on-fdb/3757 "2023-01-20T20:02:20Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![harikb](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/harikb/32/1033_2.png) [@harikb](https://forums.foundationdb.org/u/harikb)\ **Post date:** [January 20, 2023, 8:02pm UTC](https://forums.foundationdb.org/t/disk-snapshots-on-fdb/3757/1 "2023-01-20T20:02:20Z")
Hello folks, I am trying to understand how disk snapshots work (technical details). When the `snapshot` command is issued and it runs the whitelisted binary, I get that file-system snapshot / copy is outside of the FDB logic and done by underlying filesystem / tool. However, what happens to transactions that are in progress. How does the restored instance know to discard uncommitted data. I don’t see any read-version numbers passed to the snapshot binary. Senthil’s [talk](https://www.youtube.com/watch?v=hxjAS_1_qbE&t=252s) did mention that version-number is passed around, but can I assume this is internally handled by the sequence he is describing? In addition, is there a requirement that the snapshot binary finish within the typical 5-second txn time limit? Is the DB locked or write-transactions blocked during this process? His talk also started a workload in parallel, but he didn’t mention if the write transactions waited/hung during the snapshot process. I appreciate any pointers. Thanks – Hari ---
**Author:** ![Rjerk](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/rjerk/32/1056_2.png) [@Rjerk](https://forums.foundationdb.org/u/Rjerk)\ **Post date:** [September 1, 2023, 3:35am UTC](https://forums.foundationdb.org/t/disk-snapshots-on-fdb/3757/2 "2023-09-01T03:35:26Z")
Hi, I’m also curious, do you have answers?