diff --git a/configure.ac b/configure.ac
index f168f894ce..a867933866 100644
--- a/configure.ac
+++ b/configure.ac
@@ -253,10 +253,10 @@ AC_CHECK_SIZEOF([long])
 
 dnl Availability of various common functions (non-fatal if missing),
 dnl and various less common threadsafe functions
-AC_CHECK_FUNCS_ONCE([cfmakeraw geteuid getgid getgrnam_r getmntent_r \
-  getpwuid_r getuid kill mmap newlocale posix_fallocate posix_memalign \
-  prlimit regexec sched_getaffinity setgroups setns setrlimit symlink \
-  sysctlbyname])
+AC_CHECK_FUNCS_ONCE([cfmakeraw fallocate geteuid getgid getgrnam_r \
+  getmntent_r getpwuid_r getuid kill mmap newlocale posix_fallocate \
+  posix_memalign prlimit regexec sched_getaffinity setgroups setns \
+  setrlimit symlink sysctlbyname])
 
 dnl Availability of pthread functions (if missing, win32 threading is
 dnl assumed).  Because of $LIB_PTHREAD, we cannot use AC_CHECK_FUNCS_ONCE.
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index b7edf85950..5f1bc66971 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -129,7 +129,7 @@ virStorageBackendCopyToFD(virStorageVolDefPtr vol,
                           virStorageVolDefPtr inputvol,
                           int fd,
                           unsigned long long *total,
-                          int is_dest_file)
+                          int want_sparse)
 {
     int inputfd = -1;
     int amtread = -1;
@@ -191,7 +191,7 @@ virStorageBackendCopyToFD(virStorageVolDefPtr vol,
             interval = ((wbytes > amtleft) ? amtleft : wbytes);
             int offset = amtread - amtleft;
 
-            if (is_dest_file && memcmp(buf+offset, zerobuf, interval) == 0) {
+            if (want_sparse && memcmp(buf+offset, zerobuf, interval) == 0) {
                 if (lseek(fd, interval, SEEK_CUR) < 0) {
                     ret = -errno;
                     virReportSystemError(errno,
@@ -315,6 +315,7 @@ static int
 createRawFile(int fd, virStorageVolDefPtr vol,
               virStorageVolDefPtr inputvol)
 {
+    int need_alloc = 1;
     int ret = 0;
     unsigned long long remain;
 
@@ -328,17 +329,41 @@ createRawFile(int fd, virStorageVolDefPtr vol,
         goto cleanup;
     }
 
+#ifdef HAVE_FALLOCATE
+    /* Try to preallocate all requested disk space, but fall back to
+     * other methods if this fails with ENOSYS or EOPNOTSUPP.
+     * NOTE: do not use posix_fallocate; posix_fallocate falls back
+     * to writing zeroes block by block in case fallocate isn't
+     * available, and since we're going to copy data from another
+     * file it doesn't make sense to write the file twice. */
+    if (fallocate(fd, 0, 0, vol->allocation) == 0) {
+        need_alloc = 0;
+    } else if (errno != ENOSYS && errno != EOPNOTSUPP) {
+        ret = -errno;
+        virReportSystemError(errno,
+                             _("cannot allocate %llu bytes in file '%s'"),
+                             vol->allocation, vol->target.path);
+        goto cleanup;
+    }
+#endif
+
     remain = vol->allocation;
 
     if (inputvol) {
-        ret = virStorageBackendCopyToFD(vol, inputvol, fd, &remain, 1);
+        /* allow zero blocks to be skipped if we've requested sparse
+         * allocation (allocation < capacity) or we have already
+         * been able to allocate the required space. */
+        int want_sparse = (need_alloc == 0) ||
+                          (vol->allocation < inputvol->capacity);
+
+        ret = virStorageBackendCopyToFD(vol, inputvol, fd, &remain, want_sparse);
         if (ret < 0) {
             goto cleanup;
         }
     }
 
-    if (remain) {
-        if (safezero(fd, 0, remain) < 0) {
+    if (remain && need_alloc) {
+        if (safezero(fd, vol->allocation - remain, remain) < 0) {
             ret = -errno;
             virReportSystemError(errno, _("cannot fill file '%s'"),
                                  vol->target.path);