diff --git a/yama/src/operations/checking.rs b/yama/src/operations/checking.rs
index 8b13789..37c85ba 100644
--- a/yama/src/operations/checking.rs
+++ b/yama/src/operations/checking.rs
@@ -1 +1,223 @@
+use crate::chunking::RecursiveUnchunker;
+use crate::commands::retrieve_tree_node;
+use crate::definitions::{ChunkId, TreeNode};
+use crate::pile::{Keyspace, Pile, RawPile};
+use anyhow::bail;
+use indicatif::{ProgressBar, ProgressDrawTarget, ProgressStyle};
+use log::{error, info, warn};
+use std::collections::HashSet;
+use std::io::Write;
+use std::sync::Mutex;
 
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+pub enum VacuumMode {
+    NoVacuum,
+    DryRunVacuum,
+    Vacuum,
+}
+
+pub struct NullWriter {}
+
+impl Write for NullWriter {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
+/// Mark-and-sweep style vacuuming system.
+pub struct VacuumRawPile<RP: RawPile> {
+    underlying: RP,
+    vacuum_tracking_enabled: bool,
+    retrieved_chunks: Mutex<HashSet<ChunkId>>,
+}
+
+impl<RP: RawPile> VacuumRawPile<RP> {
+    pub fn new(underlying: RP, vacuum_tracking_enabled: bool) -> Self {
+        VacuumRawPile {
+            underlying,
+            vacuum_tracking_enabled,
+            retrieved_chunks: Default::default(),
+        }
+    }
+
+    pub fn calculate_vacuum_for_sweeping(&self) -> anyhow::Result<HashSet<ChunkId>> {
+        if !self.vacuum_tracking_enabled {
+            bail!("Vacuum tracking not enabled, you can't calculate the vacuum set!");
+        }
+
+        let mut to_sweep = HashSet::new();
+
+        let retrieved_chunks = self.retrieved_chunks.lock().unwrap();
+
+        let mut chunk_id: ChunkId = Default::default();
+        for key in self.list_keys(Keyspace::Chunk)? {
+            chunk_id.clone_from_slice(&key?);
+            if !retrieved_chunks.contains(&chunk_id) {
+                to_sweep.insert(chunk_id.clone());
+            }
+        }
+
+        Ok(to_sweep)
+    }
+}
+
+impl<RP: RawPile> RawPile for VacuumRawPile<RP> {
+    fn exists(&self, kind: Keyspace, key: &[u8]) -> anyhow::Result<bool> {
+        self.underlying.exists(kind, key)
+    }
+
+    fn read(&self, kind: Keyspace, key: &[u8]) -> anyhow::Result<Option<Vec<u8>>> {
+        self.underlying.read(kind, key)
+    }
+
+    fn write(&self, kind: Keyspace, key: &[u8], value: &[u8]) -> anyhow::Result<()> {
+        if self.vacuum_tracking_enabled && kind == Keyspace::Chunk {
+            let mut chunk_id: ChunkId = Default::default();
+            chunk_id.clone_from_slice(key);
+            self.retrieved_chunks.lock().unwrap().insert(chunk_id);
+        }
+        self.underlying.write(kind, key, value)
+    }
+
+    fn delete(&self, kind: Keyspace, key: &[u8]) -> anyhow::Result<()> {
+        self.underlying.delete(kind, key)
+    }
+
+    fn list_keys(
+        &self,
+        kind: Keyspace,
+    ) -> anyhow::Result<Box<dyn Iterator<Item = anyhow::Result<Vec<u8>>>>> {
+        self.underlying.list_keys(kind)
+    }
+
+    fn flush(&self) -> anyhow::Result<()> {
+        self.underlying.flush()
+    }
+
+    fn check_lowlevel(&self) -> anyhow::Result<bool> {
+        self.underlying.check_lowlevel()
+    }
+}
+
+pub fn check_deep<RP: RawPile>(
+    pile: Pile<RP>,
+    vacuum: VacuumMode,
+    make_progress_bar: bool,
+) -> anyhow::Result<u32> {
+    let pile = Pile::new(VacuumRawPile::new(
+        pile.raw_pile,
+        vacuum != VacuumMode::NoVacuum,
+    ));
+
+    let mut errors = 0;
+
+    let mut to_check = Vec::new();
+    let pointer_list = pile.list_pointers()?;
+
+    for pointer in pointer_list.iter() {
+        info!("Checking pointer {:?}", pointer);
+        match pile.read_pointer(&pointer)? {
+            Some(pointer_data) => {
+                if let Some(parent) = pointer_data.parent_pointer {
+                    if !pointer_list.contains(&parent) {
+                        errors += 1;
+                        error!(
+                            "Pointer {:?} has a parent {:?} which does not exist.",
+                            pointer, parent
+                        );
+                    }
+                }
+
+                let tree_node = retrieve_tree_node(&pile, pointer_data.chunk_ref.clone())?;
+                tree_node.node.visit(
+                    &mut |node, _| {
+                        if let TreeNode::NormalFile { content, .. } = node {
+                            to_check.push(content.clone());
+                        }
+                        Ok(())
+                    },
+                    "".to_owned(),
+                )?;
+            }
+            None => {
+                errors += 1;
+                error!("Pointer {:?} does not seem to exist.", pointer);
+            }
+        }
+    }
+
+    let pbar = if make_progress_bar {
+        ProgressBar::with_draw_target(1000 as u64, ProgressDrawTarget::stdout_with_hz(10))
+    } else {
+        ProgressBar::hidden()
+    };
+    pbar.set_style(
+        ProgressStyle::default_bar()
+            .template("[{elapsed_precise}]/[{eta}] {bar:40.cyan/blue} {pos:>7}/{len:7} {msg}"),
+    );
+    pbar.set_message("checking");
+
+    let mut done = 0;
+
+    while let Some(next_to_check) = to_check.pop() {
+        done += 1;
+        pbar.set_length(done + to_check.len() as u64);
+        pbar.set_position(done);
+
+        let mut unchunker = RecursiveUnchunker::new(&pile, next_to_check.clone());
+        match std::io::copy(&mut unchunker, &mut NullWriter {}) {
+            Ok(_) => {}
+            Err(err) => {
+                errors += 1;
+                warn!(
+                    "Error occurred when reading {:?}: {:?}.",
+                    next_to_check, err
+                );
+            }
+        }
+    }
+
+    pbar.finish_and_clear();
+
+    if errors > 0 {
+        error!("There were {:?}", errors);
+    } else {
+        info!("No errors.");
+    }
+
+    if errors == 0 && vacuum != VacuumMode::NoVacuum {
+        info!("Calculating sweep set for vacuuming.");
+        let to_vacuum = pile.raw_pile.calculate_vacuum_for_sweeping()?;
+        info!("{} chunks are ready to be vacuumed.", to_vacuum.len());
+        if vacuum == VacuumMode::Vacuum {
+            let pbar = if make_progress_bar {
+                ProgressBar::with_draw_target(
+                    to_vacuum.len() as u64,
+                    ProgressDrawTarget::stdout_with_hz(10),
+                )
+            } else {
+                ProgressBar::hidden()
+            };
+            pbar.set_style(
+                ProgressStyle::default_bar().template(
+                    "[{elapsed_precise}]/[{eta}] {bar:40.cyan/blue} {pos:>7}/{len:7} {msg}",
+                ),
+            );
+            pbar.set_message("vacuuming");
+
+            // actually do the vacuum!
+            info!("Going to vacuum them up.");
+            for vacuum_id in to_vacuum {
+                pile.raw_pile.delete(Keyspace::Chunk, &vacuum_id)?;
+                pbar.inc(1);
+            }
+            pbar.finish_and_clear();
+        }
+    }
+
+    Ok(errors)
+}