diff --git a/server/block_processor.py b/server/block_processor.py
index 57264df..207a905 100644
--- a/server/block_processor.py
+++ b/server/block_processor.py
@@ -10,7 +10,6 @@
 
 import array
 import asyncio
-import itertools
 import os
 from struct import pack, unpack
 import time
@@ -437,47 +436,11 @@ class BlockProcessor(server.db.DB):
 
     def fs_flush(self):
         '''Flush the things stored on the filesystem.'''
-        blocks_done = len(self.headers)
-        prior_tx_count = (self.tx_counts[self.fs_height]
-                          if self.fs_height >= 0 else 0)
-        cur_tx_count = self.tx_counts[-1] if self.tx_counts else 0
-        txs_done = cur_tx_count - prior_tx_count
-
-        assert self.fs_height + blocks_done == self.height
-        assert len(self.tx_hashes) == blocks_done
-        assert len(self.tx_counts) == self.height + 1
-        assert cur_tx_count == self.tx_count, \
-            'cur: {:,d} new: {:,d}'.format(cur_tx_count, self.tx_count)
-
-        # First the headers
-        headers = b''.join(self.headers)
-        header_len = self.coin.HEADER_LEN
-        self.headers_file.seek((self.fs_height + 1) * header_len)
-        self.headers_file.write(headers)
-        self.headers_file.flush()
-
-        # Then the tx counts
-        self.txcount_file.seek((self.fs_height + 1) * self.tx_counts.itemsize)
-        self.txcount_file.write(self.tx_counts[self.fs_height + 1:])
-        self.txcount_file.flush()
-
-        # Finally the hashes
-        hashes = memoryview(b''.join(itertools.chain(*self.tx_hashes)))
-        assert len(hashes) % 32 == 0
-        assert len(hashes) // 32 == txs_done
-        cursor = 0
-        file_pos = prior_tx_count * 32
-        while cursor < len(hashes):
-            file_num, offset = divmod(file_pos, self.tx_hash_file_size)
-            size = min(len(hashes) - cursor, self.tx_hash_file_size - offset)
-            filename = 'hashes{:04d}'.format(file_num)
-            with self.open_file(filename, create=True) as f:
-                f.seek(offset)
-                f.write(hashes[cursor:cursor + size])
-            cursor += size
-            file_pos += size
-
-        os.sync()
+        assert self.fs_height + len(self.headers) == self.height
+        assert self.tx_count == self.tx_counts[-1] if self.tx_counts else 0
+
+        self.fs_update(self.fs_height, self.headers, self.tx_hashes)
+
         self.fs_height = self.height
         self.fs_tx_count = self.tx_count
         self.tx_hashes = []
@@ -819,23 +782,6 @@ class BlockProcessor(server.db.DB):
         self.db_height = self.height
         self.db_tip = self.tip
 
-    def read_headers(self, start, count):
-        # Read some from disk
-        disk_count = min(count, max(0, self.fs_height + 1 - start))
-        result = self.fs_read_headers(start, disk_count)
-        count -= disk_count
-        start += disk_count
-
-        # The rest from memory
-        if count:
-            start -= self.fs_height + 1
-            if not (count >= 0 and start + count <= len(self.headers)):
-                raise ChainError('{:,d} headers starting at {:,d} not on disk'
-                                 .format(count, start))
-            result += b''.join(self.headers[start: start + count])
-
-        return result
-
     def get_tx_hash(self, tx_num):
         '''Returns the tx_hash and height of a tx number.'''
         tx_hash, tx_height = self.fs_tx_hash(tx_num)
diff --git a/server/db.py b/server/db.py
index 609537e..376cb0f 100644
--- a/server/db.py
+++ b/server/db.py
@@ -10,6 +10,7 @@
 
 import array
 import ast
+import itertools
 import os
 from struct import pack, unpack
 from bisect import bisect_right
@@ -117,7 +118,6 @@ class DB(LoggedClass):
             self.logger.info('sync time so far: {}'
                              .format(formatted_time(self.wall_time)))
 
-
     def write_state(self, batch):
         '''Write chain state to the batch.'''
         state = {
@@ -142,7 +142,51 @@ class DB(LoggedClass):
                 return open(filename, 'wb+')
             raise
 
-    def fs_read_headers(self, start, count):
+    def fs_update(self, fs_height, headers, block_tx_hashes):
+        '''Write headers, the tx_count array and block tx hashes to disk.
+
+        Their first height is fs_height.  No recorded DB state is
+        updated.  These arrays are all append only, so in a crash we
+        just pick up again from the DB height.
+        '''
+        blocks_done = len(self.headers)
+        new_height = fs_height + blocks_done
+        prior_tx_count = (self.tx_counts[fs_height] if fs_height >= 0 else 0)
+        cur_tx_count = self.tx_counts[-1] if self.tx_counts else 0
+        txs_done = cur_tx_count - prior_tx_count
+
+        assert len(self.tx_hashes) == blocks_done
+        assert len(self.tx_counts) == new_height + 1
+
+        # First the headers
+        self.headers_file.seek((fs_height + 1) * self.coin.HEADER_LEN)
+        self.headers_file.write(b''.join(headers))
+        self.headers_file.flush()
+
+        # Then the tx counts
+        self.txcount_file.seek((fs_height + 1) * self.tx_counts.itemsize)
+        self.txcount_file.write(self.tx_counts[fs_height + 1:])
+        self.txcount_file.flush()
+
+        # Finally the hashes
+        hashes = memoryview(b''.join(itertools.chain(*block_tx_hashes)))
+        assert len(hashes) % 32 == 0
+        assert len(hashes) // 32 == txs_done
+        cursor = 0
+        file_pos = prior_tx_count * 32
+        while cursor < len(hashes):
+            file_num, offset = divmod(file_pos, self.tx_hash_file_size)
+            size = min(len(hashes) - cursor, self.tx_hash_file_size - offset)
+            filename = 'hashes{:04d}'.format(file_num)
+            with self.open_file(filename, create=True) as f:
+                f.seek(offset)
+                f.write(hashes[cursor:cursor + size])
+            cursor += size
+            file_pos += size
+
+        os.sync()
+
+    def read_headers(self, start, count):
         '''Requires count >= 0.'''
         # Read some from disk
         disk_count = min(count, self.db_height + 1 - start)
@@ -172,7 +216,7 @@ class DB(LoggedClass):
             return f.read(32), tx_height
 
     def fs_block_hashes(self, height, count):
-        headers = self.fs_read_headers(height, count)
+        headers = self.read_headers(height, count)
         # FIXME: move to coins.py
         hlen = self.coin.HEADER_LEN
         return [self.coin.header_hash(header)
diff --git a/server/protocol.py b/server/protocol.py
index b9f1884..8690ea9 100644
--- a/server/protocol.py
+++ b/server/protocol.py
@@ -311,7 +311,8 @@ class ServerManager(util.LoggedClass):
         for session in self.sessions:
             if isinstance(session, ElectrumX):
                 # Use a tuple to distinguish from JSON
-                session.messages.put_nowait((self.bp.height, touched, cache))
+                triple = (self.bp.db_height, touched, cache)
+                session.messages.put_nowait(triple)
 
     async def shutdown(self):
         '''Call to shutdown the servers.  Returns when done.'''
@@ -377,7 +378,7 @@ class ServerManager(util.LoggedClass):
     async def rpc_getinfo(self, params):
         '''The RPC 'getinfo' call.'''
         return {
-            'blocks': self.bp.height,
+            'blocks': self.bp.db_height,
             'peers': len(self.irc.peers),
             'sessions': self.session_count(),
             'watched': self.subscription_count,
@@ -592,8 +593,8 @@ class ElectrumX(Session):
                              .format(self.peername(), len(matches)))
 
     def height(self):
-        '''Return the block processor's current height.'''
-        return self.bp.height
+        '''Return the current flushed database height.'''
+        return self.bp.db_height
 
     def current_electrum_header(self):
         '''Used as response to a headers subscription request.'''