diff --git a/nixos-modules/hydra.nix b/nixos-modules/hydra.nix
index 97906cb34..d001675da 100644
--- a/nixos-modules/hydra.nix
+++ b/nixos-modules/hydra.nix
@@ -464,10 +464,12 @@ in
           ''
             set -eou pipefail
             compression=$(sed -nr 's/compress_build_logs_compression = ()/\1/p' ${baseDir}/hydra.conf)
-            if [[ $compression == zstd ]]; then
+            if [[ $compression == "" ]]; then
+              compression="bzip2"
+            elif [[ $compression == zstd ]]; then
               compression="zstd --rm"
             fi
-            find ${baseDir}/build-logs -type f -name "*.drv" -mtime +3 -size +0c | xargs -r $compression --force --quiet
+            find ${baseDir}/build-logs -type f -name "*.drv" -mtime +3 -size +0c | xargs -r "$compression" --force --quiet
           '';
         startAt = "Sun 01:45";
       };
diff --git a/src/hydra-queue-runner/state.hh b/src/hydra-queue-runner/state.hh
index 5d242cdf0..839239fe7 100644
--- a/src/hydra-queue-runner/state.hh
+++ b/src/hydra-queue-runner/state.hh
@@ -23,6 +23,7 @@
 #include "nar-extractor.hh"
 #include "serve-protocol.hh"
 #include "serve-protocol-impl.hh"
+#include "serve-protocol-connection.hh"
 #include "machines.hh"
 
 
diff --git a/src/lib/Hydra/Controller/Root.pm b/src/lib/Hydra/Controller/Root.pm
index fc2651617..aa1ad5ab2 100644
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@@ -330,7 +330,7 @@ sub nar :Local :Args(1) {
     else {
         $path = $Nix::Config::storeDir . "/$path";
 
-        gone($c, "Path " . $path . " is no longer available.") unless isValidPath($path);
+        gone($c, "Path " . $path . " is no longer available.") unless $MACHINE_LOCAL_STORE->isValidPath($path);
 
         $c->stash->{current_view} = 'NixNAR';
         $c->stash->{storePath} = $path;
diff --git a/src/lib/Hydra/Plugin/S3Backup.pm b/src/lib/Hydra/Plugin/S3Backup.pm
index 98e797478..a0d678510 100644
--- a/src/lib/Hydra/Plugin/S3Backup.pm
+++ b/src/lib/Hydra/Plugin/S3Backup.pm
@@ -92,7 +92,7 @@ sub buildFinished {
         my $hash = substr basename($path), 0, 32;
         my ($deriver, $narHash, $time, $narSize, $refs) = queryPathInfo($path, 0);
         my $system;
-        if (defined $deriver and isValidPath($deriver)) {
+        if (defined $deriver and $MACHINE_LOCAL_STORE->isValidPath($deriver)) {
             $system = derivationFromPath($deriver)->{platform};
         }
         foreach my $reference (@{$refs}) {
diff --git a/src/lib/Hydra/Plugin/SubversionInput.pm b/src/lib/Hydra/Plugin/SubversionInput.pm
index 83c1f39d2..d3579c40f 100644
--- a/src/lib/Hydra/Plugin/SubversionInput.pm
+++ b/src/lib/Hydra/Plugin/SubversionInput.pm
@@ -46,7 +46,7 @@ sub fetchInput {
 
     $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
     } else {