diff --git a/fdbserver/DataDistributionTracker.actor.cpp b/fdbserver/DataDistributionTracker.actor.cpp
index 94f38622f0..40ca28aa08 100644
--- a/fdbserver/DataDistributionTracker.actor.cpp
+++ b/fdbserver/DataDistributionTracker.actor.cpp
@@ -176,8 +176,8 @@ ShardSizeBounds getShardSizeBounds(KeyRangeRef shard, int64_t maxShardSize) {
 }
 
 int64_t getMaxShardSize(double dbSizeEstimate) {
-	return std::min((SERVER_KNOBS->MIN_SHARD_BYTES +
-	                 (int64_t)std::sqrt(dbSizeEstimate) * SERVER_KNOBS->SHARD_BYTES_PER_SQRT_BYTES) *
+	return std::min((SERVER_KNOBS->MIN_SHARD_BYTES + (int64_t)std::sqrt(std::max<double>(dbSizeEstimate, 0)) *
+	                                                     SERVER_KNOBS->SHARD_BYTES_PER_SQRT_BYTES) *
 	                    SERVER_KNOBS->SHARD_BYTES_RATIO,
 	                (int64_t)SERVER_KNOBS->MAX_SHARD_BYTES);
 }