Checksum the data when writing and reading ledger snapshots

- Allow skipping snapshot checksum check - Generalise `Test/Ouroboros/Storage/LedgerDB/OnDisk.hs` - Restrict `Ord` instance for `DiskSnapshot` to `dsNumber` - Use the `Ord` instance in `listSnapshots` - Connect snapshot checksum with the node interface: - Add `Flag "DoDiskSnapshotChecksum"` to `DiskPolicyArgs` - Expose `(No)DoDiskSnapshotChecksum` in Ouroboros.Consensus.Node - Re-export `Flag` from `DiskPolicy` Update changelog
IntersectMBO · Dec 10, 2024 · 1ec6cdc · 1ec6cdc
1 parent b8a13dd
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diff --git a/ouroboros-consensus-cardano/app/DBAnalyser/Parsers.hs b/ouroboros-consensus-cardano/app/DBAnalyser/Parsers.hs
@@ -1,6 +1,7 @@
-{-# LANGUAGE ApplicativeDo #-}
-{-# LANGUAGE CPP           #-}
-{-# LANGUAGE LambdaCase    #-}
+{-# LANGUAGE ApplicativeDo      #-}
+{-# LANGUAGE CPP                #-}
+{-# LANGUAGE LambdaCase         #-}
+{-# LANGUAGE PatternSynonyms    #-}
 
 module DBAnalyser.Parsers (
     BlockType (..)
@@ -21,6 +22,7 @@ import           Options.Applicative
 import           Ouroboros.Consensus.Block
 import           Ouroboros.Consensus.Byron.Node (PBftSignatureThreshold (..))
 import           Ouroboros.Consensus.Shelley.Node (Nonce (..))
+import           Ouroboros.Consensus.Storage.LedgerDB.DiskPolicy (pattern DoDiskSnapshotChecksum, pattern NoDoDiskSnapshotChecksum)
 
 {-------------------------------------------------------------------------------
   Parsing
@@ -44,6 +46,10 @@ parseDBAnalyserConfig = DBAnalyserConfig
     <*> parseValidationPolicy
     <*> parseAnalysis
     <*> parseLimit
+    <*> flag NoDoDiskSnapshotChecksum DoDiskSnapshotChecksum (mconcat [
+            long "do-disk-snapshot-checksum"
+          , help "Check the '.checksum' file if reading a ledger snapshot"
+          ])
 
 parseSelectDB :: Parser SelectDB
 parseSelectDB =

diff --git a/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Analysis.hs b/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Analysis.hs
@@ -6,6 +6,7 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TupleSections #-}
 {-# LANGUAGE TypeApplications #-}
@@ -72,7 +73,7 @@ import           Ouroboros.Consensus.Storage.Common (BlockComponent (..))
 import           Ouroboros.Consensus.Storage.ImmutableDB (ImmutableDB)
 import qualified Ouroboros.Consensus.Storage.ImmutableDB as ImmutableDB
 import           Ouroboros.Consensus.Storage.LedgerDB (DiskSnapshot (..),
-                     writeSnapshot)
+                     pattern NoDoDiskSnapshotChecksum, writeSnapshot)
 import           Ouroboros.Consensus.Storage.Serialisation (encodeDisk)
 import           Ouroboros.Consensus.Util ((..:))
 import qualified Ouroboros.Consensus.Util.IOLike as IOLike
@@ -422,7 +423,7 @@ storeLedgerStateAt slotNo ledgerAppMode env = do
     storeLedgerState ledgerState = case pointSlot pt of
         NotOrigin slot -> do
           let snapshot = DiskSnapshot (unSlotNo slot) (Just "db-analyser")
-          writeSnapshot ledgerDbFS encLedger snapshot ledgerState
+          writeSnapshot ledgerDbFS NoDoDiskSnapshotChecksum encLedger snapshot ledgerState
           traceWith tracer $ SnapshotStoredEvent slot
         Origin -> pure ()
       where

diff --git a/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Run.hs b/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Run.hs
@@ -51,7 +51,7 @@ analyse ::
   => DBAnalyserConfig
   -> Args blk
   -> IO (Maybe AnalysisResult)
-analyse DBAnalyserConfig{analysis, confLimit, dbDir, selectDB, validation, verbose} args =
+analyse DBAnalyserConfig{analysis, confLimit, dbDir, selectDB, validation, verbose, diskSnapshotChecksum} args =
     withRegistry $ \registry -> do
       lock           <- newMVar ()
       chainDBTracer  <- mkTracer lock verbose
@@ -92,6 +92,7 @@ analyse DBAnalyserConfig{analysis, confLimit, dbDir, selectDB, validation, verbo
                 ledgerDbFS
                 (decodeDiskExtLedgerState $ configCodec cfg)
                 decode
+                diskSnapshotChecksum
                 (DiskSnapshot slot (Just "db-analyser"))
                 -- TODO @readSnapshot@ has type @ExceptT ReadIncrementalErr m
                 -- (ExtLedgerState blk)@ but it also throws exceptions! This makes

diff --git a/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Types.hs b/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Types.hs
@@ -1,20 +1,23 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 
 module Cardano.Tools.DBAnalyser.Types (module Cardano.Tools.DBAnalyser.Types) where
 
 import           Data.Word
 import           Ouroboros.Consensus.Block
+import           Ouroboros.Consensus.Util (Flag)
 
 data SelectDB =
     SelectImmutableDB (WithOrigin SlotNo)
 
 data DBAnalyserConfig = DBAnalyserConfig {
-    dbDir      :: FilePath
-  , verbose    :: Bool
-  , selectDB   :: SelectDB
-  , validation :: Maybe ValidateBlocks
-  , analysis   :: AnalysisName
-  , confLimit  :: Limit
+    dbDir                :: FilePath
+  , verbose              :: Bool
+  , selectDB             :: SelectDB
+  , validation           :: Maybe ValidateBlocks
+  , analysis             :: AnalysisName
+  , confLimit            :: Limit
+  , diskSnapshotChecksum :: Flag "DoDiskSnapshotChecksum"
   }
 
 data AnalysisName =

diff --git a/ouroboros-consensus-cardano/test/tools-test/Main.hs b/ouroboros-consensus-cardano/test/tools-test/Main.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE PatternSynonyms #-}
+
 module Main (main) where
 
 import qualified Cardano.Tools.DBAnalyser.Block.Cardano as Cardano
@@ -8,6 +10,8 @@ import qualified Cardano.Tools.DBSynthesizer.Run as DBSynthesizer
 import           Cardano.Tools.DBSynthesizer.Types
 import           Ouroboros.Consensus.Block
 import           Ouroboros.Consensus.Cardano.Block
+import           Ouroboros.Consensus.Storage.LedgerDB.DiskPolicy
+                     (pattern NoDoDiskSnapshotChecksum)
 import qualified Test.Cardano.Tools.Headers
 import           Test.Tasty
 import           Test.Tasty.HUnit
@@ -68,6 +72,7 @@ testAnalyserConfig =
     , validation  = Just ValidateAllBlocks
     , analysis    = CountBlocks
     , confLimit   = Unlimited
+    , diskSnapshotChecksum = NoDoDiskSnapshotChecksum
     }
 
 testBlockArgs :: Cardano.Args (CardanoBlock StandardCrypto)

diff --git a/ouroboros-consensus-diffusion/src/ouroboros-consensus-diffusion/Ouroboros/Consensus/Node.hs b/ouroboros-consensus-diffusion/src/ouroboros-consensus-diffusion/Ouroboros/Consensus/Node.hs
@@ -6,6 +6,7 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE MonadComprehensions #-}
 {-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE Rank2Types #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE ScopedTypeVariables #-}
@@ -51,6 +52,8 @@ module Ouroboros.Consensus.Node (
   , RunNodeArgs (..)
   , Tracers
   , Tracers' (..)
+  , pattern DoDiskSnapshotChecksum
+  , pattern NoDoDiskSnapshotChecksum
     -- * Internal helpers
   , mkNodeKernelArgs
   , nodeKernelArgsEnforceInvariants
@@ -107,7 +110,8 @@ import           Ouroboros.Consensus.Storage.ChainDB (ChainDB, ChainDbArgs,
 import qualified Ouroboros.Consensus.Storage.ChainDB as ChainDB
 import qualified Ouroboros.Consensus.Storage.ChainDB.Impl.Args as ChainDB
 import           Ouroboros.Consensus.Storage.LedgerDB.DiskPolicy
-                     (DiskPolicyArgs (..))
+                     (DiskPolicyArgs (..), pattern DoDiskSnapshotChecksum,
+                     pattern NoDoDiskSnapshotChecksum)
 import           Ouroboros.Consensus.Util.Args
 import           Ouroboros.Consensus.Util.IOLike
 import           Ouroboros.Consensus.Util.Orphans ()

diff --git a/...sensus/changelog.d/20241128_084625_georgy.lukyanov_892_checksum_snaphot_file.md b/...sensus/changelog.d/20241128_084625_georgy.lukyanov_892_checksum_snaphot_file.md
@@ -0,0 +1,14 @@
+### Breaking
+
+- When writing a ledger state snapshot to disk, calculate the state's CRC32 checksum and write it to a separate file, which is named the same as the snapshot file, plus the `.checksum` extension.
+- When reading a snapshot file in `readSnapshot`, calculate its checksum and compare it to the value in the corresponding `.checksum` file. Return an error if the checksum is different or invalid. Issue a warning if the checksum file does not exist, but still initialise the ledger DB.
+- To support the previous item, change the error type of the `readSnapshot` from `ReadIncrementalErr` to the extended `ReadSnaphotErr`.
+- Checksumming the snapshots is controlled via the `doChecksum :: Flag "DoDiskSnapshotChecksum"` parameter of `initFromSnapshot`. Ultimately, this parameter comes from the Node's configuration file via the `DiskPolicy` data type.
+- Extend the `DiskPolicyArgs` data type to enable the node to pass `Flag "DoDiskSnapshotChecksum"` to Consensus.
+
+### Non-breaking
+
+- Make `Ouroboros.Consensus.Util.CBOR.readIncremental` optionally compute the checksum of the data as it is read.
+- Introduce an explicit `Ord` instance for `DiskSnapshot` that compares the values on `dsNumber`.
+- Introduce a new utility newtype `Flag` to represent type-safe boolean flags. See ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Util.hs.
+- Use `Flag "DoDiskSnapshotChecksum"` to control the check of the snapshot checksum file in `takeSnapshot`, `readSnapshot` and `writeSnapshot`.
diff --git a/...boros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/LgrDB.hs b/...boros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/LgrDB.hs
@@ -222,6 +222,7 @@ initFromDisk ::
 initFromDisk LgrDbArgs { lgrHasFS = hasFS, .. }
              replayTracer
              immutableDB = wrapFailure (Proxy @blk) $ do
+    let LedgerDB.DiskPolicyArgs _ _ doDiskSnapshotChecksum = lgrDiskPolicyArgs
     (_initLog, db, replayed) <-
       LedgerDB.initLedgerDB
         replayTracer
@@ -232,6 +233,7 @@ initFromDisk LgrDbArgs { lgrHasFS = hasFS, .. }
         lgrConfig
         lgrGenesis
         (streamAPI immutableDB)
+        doDiskSnapshotChecksum
     return (db, replayed)
   where
     ccfg = configCodec $ getExtLedgerCfg $ LedgerDB.ledgerDbCfg lgrConfig
@@ -280,11 +282,12 @@ takeSnapshot ::
      , IsLedger (LedgerState blk)
      )
   => LgrDB m blk -> m (Maybe (LedgerDB.DiskSnapshot, RealPoint blk))
-takeSnapshot lgrDB@LgrDB{ cfg, tracer, hasFS } = wrapFailure (Proxy @blk) $ do
+takeSnapshot lgrDB@LgrDB{ cfg, tracer, hasFS, diskPolicy } = wrapFailure (Proxy @blk) $ do
     ledgerDB <- LedgerDB.ledgerDbAnchor <$> atomically (getCurrent lgrDB)
     LedgerDB.takeSnapshot
       tracer
       hasFS
+      (LedgerDB.onDiskShouldChecksumSnapshots diskPolicy)
       (encodeDiskExtLedgerState ccfg)
       ledgerDB
   where

diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE PatternSynonyms #-}
+
 -- | The Ledger DB is responsible for the following tasks:
 --
 -- - __Maintaining the in-memory ledger state at the tip__: When we try to
@@ -134,6 +136,8 @@ module Ouroboros.Consensus.Storage.LedgerDB (
   , SnapshotFailure (..)
   , diskSnapshotIsTemporary
   , listSnapshots
+  , pattern DoDiskSnapshotChecksum
+  , pattern NoDoDiskSnapshotChecksum
   , readSnapshot
     -- ** Write to disk
   , takeSnapshot
@@ -160,7 +164,9 @@ module Ouroboros.Consensus.Storage.LedgerDB (
 import           Ouroboros.Consensus.Storage.LedgerDB.DiskPolicy
                      (DiskPolicy (..), DiskPolicyArgs (..),
                      NumOfDiskSnapshots (..), SnapshotInterval (..),
-                     TimeSinceLast (..), defaultDiskPolicyArgs, mkDiskPolicy)
+                     TimeSinceLast (..), defaultDiskPolicyArgs, mkDiskPolicy,
+                     pattern DoDiskSnapshotChecksum,
+                     pattern NoDoDiskSnapshotChecksum)
 import           Ouroboros.Consensus.Storage.LedgerDB.Init (InitLog (..),
                      ReplayGoal (..), ReplayStart (..), TraceReplayEvent (..),
                      decorateReplayTracerWithGoal,

diff --git a/...oros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/DiskPolicy.hs b/...oros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/DiskPolicy.hs
@@ -3,6 +3,7 @@
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE DerivingVia #-}
 {-# LANGUAGE NumericUnderscores #-}
+{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE RecordWildCards #-}
 
 module Ouroboros.Consensus.Storage.LedgerDB.DiskPolicy (
@@ -13,6 +14,10 @@ module Ouroboros.Consensus.Storage.LedgerDB.DiskPolicy (
   , TimeSinceLast (..)
   , defaultDiskPolicyArgs
   , mkDiskPolicy
+  , pattern DoDiskSnapshotChecksum
+  , pattern NoDoDiskSnapshotChecksum
+    -- * Re-exports
+  , Flag (..)
   ) where
 
 import           Control.Monad.Class.MonadTime.SI
@@ -21,6 +26,7 @@ import           Data.Word
 import           GHC.Generics
 import           NoThunks.Class (NoThunks, OnlyCheckWhnf (..))
 import           Ouroboros.Consensus.Config.SecurityParam
+import           Ouroboros.Consensus.Util (Flag (..))
 
 -- | Length of time, requested by the user, that has to pass after which
 -- a snapshot is taken. It can be:
@@ -41,7 +47,11 @@ data NumOfDiskSnapshots =
   | RequestedNumOfDiskSnapshots Word
   deriving stock (Eq, Generic, Show)
 
-data DiskPolicyArgs = DiskPolicyArgs SnapshotInterval NumOfDiskSnapshots
+pattern DoDiskSnapshotChecksum, NoDoDiskSnapshotChecksum :: Flag "DoDiskSnapshotChecksum"
+pattern DoDiskSnapshotChecksum = Flag True
+pattern NoDoDiskSnapshotChecksum = Flag False
+
+data DiskPolicyArgs = DiskPolicyArgs SnapshotInterval NumOfDiskSnapshots (Flag "DoDiskSnapshotChecksum")
 
 -- | On-disk policy
 --
@@ -67,7 +77,7 @@ data DiskPolicy = DiskPolicy {
       --        the next snapshot, we delete the oldest one, leaving the middle
       --        one available in case of truncation of the write. This is
       --        probably a sane value in most circumstances.
-      onDiskNumSnapshots       :: Word
+      onDiskNumSnapshots            :: Word
 
       -- | Should we write a snapshot of the ledger state to disk?
       --
@@ -87,7 +97,11 @@ data DiskPolicy = DiskPolicy {
       --   blocks had to be replayed.
       --
       -- See also 'mkDiskPolicy'
-    , onDiskShouldTakeSnapshot :: TimeSinceLast DiffTime -> Word64 -> Bool
+    , onDiskShouldTakeSnapshot      :: TimeSinceLast DiffTime -> Word64 -> Bool
+
+    -- | Whether or not to checksum the ledger snapshots to detect data corruption on disk.
+    -- "yes" if @'DoDiskSnapshotChecksum'@; "no" if @'NoDoDiskSnapshotChecksum'@.
+    , onDiskShouldChecksumSnapshots :: Flag "DoDiskSnapshotChecksum"
     }
   deriving NoThunks via OnlyCheckWhnf DiskPolicy
 
@@ -97,10 +111,10 @@ data TimeSinceLast time = NoSnapshotTakenYet | TimeSinceLast time
 -- | Default on-disk policy arguments suitable to use with cardano-node
 --
 defaultDiskPolicyArgs :: DiskPolicyArgs
-defaultDiskPolicyArgs = DiskPolicyArgs DefaultSnapshotInterval DefaultNumOfDiskSnapshots
+defaultDiskPolicyArgs = DiskPolicyArgs DefaultSnapshotInterval DefaultNumOfDiskSnapshots DoDiskSnapshotChecksum
 
 mkDiskPolicy :: SecurityParam -> DiskPolicyArgs -> DiskPolicy
-mkDiskPolicy (SecurityParam k) (DiskPolicyArgs reqInterval reqNumOfSnapshots) =
+mkDiskPolicy (SecurityParam k) (DiskPolicyArgs reqInterval reqNumOfSnapshots onDiskShouldChecksumSnapshots) =
   DiskPolicy {..}
   where
     onDiskNumSnapshots :: Word

diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/Init.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/Init.hs
@@ -1,5 +1,7 @@
 {-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 
@@ -31,10 +33,14 @@ import           Ouroboros.Consensus.Ledger.Extended
 import           Ouroboros.Consensus.Ledger.Inspect
 import           Ouroboros.Consensus.Ledger.SupportsProtocol
 import           Ouroboros.Consensus.Storage.ImmutableDB.Stream
+import           Ouroboros.Consensus.Storage.LedgerDB.DiskPolicy
+                     (pattern DoDiskSnapshotChecksum,
+                     pattern NoDoDiskSnapshotChecksum)
 import           Ouroboros.Consensus.Storage.LedgerDB.LedgerDB
 import           Ouroboros.Consensus.Storage.LedgerDB.Query
 import           Ouroboros.Consensus.Storage.LedgerDB.Snapshots
 import           Ouroboros.Consensus.Storage.LedgerDB.Update
+import           Ouroboros.Consensus.Util (Flag)
 import           Ouroboros.Consensus.Util.IOLike
 import           Ouroboros.Network.Block (Point (Point))
 import           System.FS.API
@@ -102,6 +108,7 @@ initLedgerDB ::
   -> LedgerDbCfg (ExtLedgerState blk)
   -> m (ExtLedgerState blk) -- ^ Genesis ledger state
   -> StreamAPI m blk blk
+  -> Flag "DoDiskSnapshotChecksum"
   -> m (InitLog blk, LedgerDB' blk, Word64)
 initLedgerDB replayTracer
              tracer
@@ -110,14 +117,16 @@ initLedgerDB replayTracer
              decHash
              cfg
              getGenesisLedger
-             stream = do
+             stream
+             doDoDiskSnapshotChecksum = do
     snapshots <- listSnapshots hasFS
-    tryNewestFirst id snapshots
+    tryNewestFirst doDoDiskSnapshotChecksum id snapshots
   where
-    tryNewestFirst :: (InitLog blk -> InitLog blk)
+    tryNewestFirst :: Flag "DoDiskSnapshotChecksum"
+                   -> (InitLog blk -> InitLog blk)
                    -> [DiskSnapshot]
                    -> m (InitLog blk, LedgerDB' blk, Word64)
-    tryNewestFirst acc [] = do
+    tryNewestFirst _ acc [] = do
         -- We're out of snapshots. Start at genesis
         traceWith replayTracer ReplayFromGenesis
         initDb <- ledgerDbWithAnchor <$> getGenesisLedger
@@ -126,8 +135,7 @@ initLedgerDB replayTracer
         case ml of
           Left _  -> error "invariant violation: invalid current chain"
           Right (l, replayed) -> return (acc InitFromGenesis, l, replayed)
-    tryNewestFirst acc (s:ss) = do
-        -- If we fail to use this snapshot, delete it and try an older one
+    tryNewestFirst doChecksum acc allSnapshot@(s:ss) = do
         ml <- runExceptT $ initFromSnapshot
                              replayTracer
                              hasFS
@@ -136,14 +144,23 @@ initLedgerDB replayTracer
                              cfg
                              stream
                              s
+                             doChecksum
         case ml of
+          -- If a checksum file is missing for a snapshot,
+          -- issue a warning and retry the same snapshot
+          -- ignoring the checksum
+          Left (InitFailureRead ReadSnapshotNoChecksumFile{}) -> do
+            traceWith tracer $ SnapshotMissingChecksum s
+            tryNewestFirst NoDoDiskSnapshotChecksum acc allSnapshot
+          -- If we fail to use this snapshot for any other reason, delete it and try an older one
           Left err -> do
             when (diskSnapshotIsTemporary s) $
               -- We don't delete permanent snapshots, even if we couldn't parse
               -- them
               deleteSnapshot hasFS s
             traceWith tracer $ InvalidSnapshot s err
-            tryNewestFirst (acc . InitFailure s err) ss
+            -- always reset checksum flag after failure
+            tryNewestFirst DoDiskSnapshotChecksum (acc . InitFailure s err) ss
           Right (r, l, replayed) ->
             return (acc (InitFromSnapshot s r), l, replayed)
 
@@ -170,10 +187,11 @@ initFromSnapshot ::
   -> LedgerDbCfg (ExtLedgerState blk)
   -> StreamAPI m blk blk
   -> DiskSnapshot
+  -> Flag "DoDiskSnapshotChecksum"
   -> ExceptT (SnapshotFailure blk) m (RealPoint blk, LedgerDB' blk, Word64)
-initFromSnapshot tracer hasFS decLedger decHash cfg stream ss = do
+initFromSnapshot tracer hasFS decLedger decHash cfg stream ss doChecksum = do
     initSS <- withExceptT InitFailureRead $
-                readSnapshot hasFS decLedger decHash ss
+                readSnapshot hasFS decLedger decHash doChecksum ss
     let replayStart = castPoint $ getTip initSS
     case pointToWithOriginRealPoint replayStart of
       Origin -> throwError InitFailureGenesis