diff --git a/walkeeper/src/bin/safekeeper.rs b/walkeeper/src/bin/safekeeper.rs
index 4c4e3eff5b..618467ef65 100644
--- a/walkeeper/src/bin/safekeeper.rs
+++ b/walkeeper/src/bin/safekeeper.rs
@@ -79,7 +79,10 @@ fn main() -> Result<()> {
         .get_matches();
 
     let mut conf = SafeKeeperConf {
-        data_dir: PathBuf::from("./"),
+        // Always set to './'. We will chdir into the directory specified on the
+        // command line, so that when the server is running, all paths are relative
+        // to that.
+        workdir: PathBuf::from("./"),
         daemonize: false,
         no_sync: false,
         pageserver_addr: None,
@@ -91,10 +94,8 @@ fn main() -> Result<()> {
     };
 
     if let Some(dir) = arg_matches.value_of("datadir") {
-        conf.data_dir = PathBuf::from(dir);
-
         // change into the data directory.
-        std::env::set_current_dir(&conf.data_dir)?;
+        std::env::set_current_dir(PathBuf::from(dir))?;
     }
 
     if arg_matches.is_present("no-sync") {
@@ -129,8 +130,7 @@ fn main() -> Result<()> {
 }
 
 fn start_safekeeper(conf: SafeKeeperConf) -> Result<()> {
-    let log_filename = conf.data_dir.join("safekeeper.log");
-    let log_file = logging::init(log_filename, conf.daemonize)?;
+    let log_file = logging::init("safekeeper.log", conf.daemonize)?;
 
     let http_listener = TcpListener::bind(conf.listen_http_addr.clone()).map_err(|e| {
         error!("failed to bind to address {}: {}", conf.listen_http_addr, e);
diff --git a/walkeeper/src/lib.rs b/walkeeper/src/lib.rs
index 8e9b1de77a..a961cb5dfe 100644
--- a/walkeeper/src/lib.rs
+++ b/walkeeper/src/lib.rs
@@ -24,7 +24,14 @@ pub mod defaults {
 
 #[derive(Debug, Clone)]
 pub struct SafeKeeperConf {
-    pub data_dir: PathBuf,
+    // Repository directory, relative to current working directory.
+    // Normally, the safekeeper changes the current working directory
+    // to the repository, and 'workdir' is always '.'. But we don't do
+    // that during unit testing, because the current directory is global
+    // to the process but different unit tests work on different
+    // data directories to avoid clashing with each other.
+    pub workdir: PathBuf,
+
     pub daemonize: bool,
     pub no_sync: bool,
     pub listen_pg_addr: String,
diff --git a/walkeeper/src/replication.rs b/walkeeper/src/replication.rs
index 29532f9942..6152265159 100644
--- a/walkeeper/src/replication.rs
+++ b/walkeeper/src/replication.rs
@@ -243,7 +243,7 @@ impl ReplicationConn {
                     let segno = start_pos.segment_number(wal_seg_size);
                     let wal_file_name = XLogFileName(timeline, segno, wal_seg_size);
                     let timeline_id = swh.timeline.get().timelineid.to_string();
-                    let wal_file_path = swh.conf.data_dir.join(timeline_id).join(wal_file_name);
+                    let wal_file_path = swh.conf.workdir.join(timeline_id).join(wal_file_name);
                     Self::open_wal_file(&wal_file_path)?
                 }
             };
diff --git a/walkeeper/src/s3_offload.rs b/walkeeper/src/s3_offload.rs
index 0c1630b9df..841317c848 100644
--- a/walkeeper/src/s3_offload.rs
+++ b/walkeeper/src/s3_offload.rs
@@ -54,7 +54,7 @@ async fn offload_files(
             && IsXLogFileName(entry.file_name().to_str().unwrap())
             && entry.metadata().unwrap().created().unwrap() <= horizon
         {
-            let relpath = path.strip_prefix(&conf.data_dir).unwrap();
+            let relpath = path.strip_prefix(&conf.workdir).unwrap();
             let s3path = String::from("walarchive/") + relpath.to_str().unwrap();
             if !listing.contains(&s3path) {
                 let mut file = File::open(&path)?;
@@ -97,7 +97,7 @@ async fn main_loop(conf: &SafeKeeperConf) -> Result<()> {
             .flat_map(|b| b.contents.iter().map(|o| o.key.clone()))
             .collect();
 
-        let n = offload_files(&bucket, &listing, &conf.data_dir, conf).await?;
+        let n = offload_files(&bucket, &listing, &conf.workdir, conf).await?;
         info!("Offload {} files to S3", n);
         sleep(conf.ttl.unwrap()).await;
     }
diff --git a/walkeeper/src/timeline.rs b/walkeeper/src/timeline.rs
index f3795941e1..d59ee5701c 100644
--- a/walkeeper/src/timeline.rs
+++ b/walkeeper/src/timeline.rs
@@ -114,7 +114,7 @@ impl SharedState {
             conf: conf.clone(),
         };
         let (flush_lsn, tli) = if state.server.wal_seg_size != 0 {
-            let wal_dir = conf.data_dir.join(format!("{}", timelineid));
+            let wal_dir = conf.workdir.join(format!("{}", timelineid));
             find_end_of_wal(
                 &wal_dir,
                 state.server.wal_seg_size as usize,
@@ -140,7 +140,7 @@ impl SharedState {
         create: CreateControlFile,
     ) -> Result<(File, SafeKeeperState)> {
         let control_file_path = conf
-            .data_dir
+            .workdir
             .join(timelineid.to_string())
             .join(CONTROL_FILE_NAME);
         info!(
@@ -419,12 +419,12 @@ impl Storage for FileStorage {
             let wal_file_name = XLogFileName(server.tli, segno, wal_seg_size);
             let wal_file_path = self
                 .conf
-                .data_dir
+                .workdir
                 .join(ztli.to_string())
                 .join(wal_file_name.clone());
             let wal_file_partial_path = self
                 .conf
-                .data_dir
+                .workdir
                 .join(ztli.to_string())
                 .join(wal_file_name.clone() + ".partial");