diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index bc36aef5d..eaaf9669f 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -580,7 +580,6 @@ ref<const ValidPathInfo> RemoteStore::addCAToStore(
 
                 try {
                     conn->to.written = 0;
-                    conn->to.warn = true;
                     connections->incCapacity();
                     {
                         Finally cleanup([&]() { connections->decCapacity(); });
@@ -591,7 +590,6 @@ ref<const ValidPathInfo> RemoteStore::addCAToStore(
                             dumpString(contents, conn->to);
                         }
                     }
-                    conn->to.warn = false;
                     conn.processStderr();
                 } catch (SysError & e) {
                     /* Daemon closed while we were sending the path. Probably OOM
diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 8ff904583..2c3597775 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -48,24 +48,9 @@ FdSink::~FdSink()
 }
 
 
-size_t threshold = 256 * 1024 * 1024;
-
-static void warnLargeDump()
-{
-    warn("dumping very large path (> 256 MiB); this may run out of memory");
-}
-
-
 void FdSink::write(std::string_view data)
 {
     written += data.size();
-    static bool warned = false;
-    if (warn && !warned) {
-        if (written > threshold) {
-            warnLargeDump();
-            warned = true;
-        }
-    }
     try {
         writeFull(fd, data);
     } catch (SysError & e) {
@@ -448,11 +433,6 @@ Error readError(Source & source)
 
 void StringSink::operator () (std::string_view data)
 {
-    static bool warned = false;
-    if (!warned && s.size() > threshold) {
-        warnLargeDump();
-        warned = true;
-    }
     s.append(data);
 }
 
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 13da26c6a..84847835a 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -97,19 +97,17 @@ protected:
 struct FdSink : BufferedSink
 {
     int fd;
-    bool warn = false;
     size_t written = 0;
 
     FdSink() : fd(-1) { }
     FdSink(int fd) : fd(fd) { }
     FdSink(FdSink&&) = default;
 
-    FdSink& operator=(FdSink && s)
+    FdSink & operator=(FdSink && s)
     {
         flush();
         fd = s.fd;
         s.fd = -1;
-        warn = s.warn;
         written = s.written;
         return *this;
     }