diff --git a/store/src/lmdb.rs b/store/src/lmdb.rs
index 03cf10ed8..1419fc7ae 100644
--- a/store/src/lmdb.rs
+++ b/store/src/lmdb.rs
@@ -22,11 +22,14 @@ use lmdb_zero as lmdb;
 use lmdb_zero::traits::CreateCursor;
 use lmdb_zero::LmdbResultExt;
 
+use crate::core::global;
 use crate::core::ser::{self, ProtocolVersion};
 use crate::util::{RwLock, RwLockReadGuard};
 
 /// number of bytes to grow the database by when needed
-pub const ALLOC_CHUNK_SIZE: usize = 134_217_728; //128 MB
+pub const ALLOC_CHUNK_SIZE_DEFAULT: usize = 134_217_728; //128 MB
+/// And for test mode, to avoid too much disk allocation on windows
+pub const ALLOC_CHUNK_SIZE_DEFAULT_TEST: usize = 1_048_576; //1 MB
 const RESIZE_PERCENT: f32 = 0.9;
 /// Want to ensure that each resize gives us at least this %
 /// of total space free
@@ -73,6 +76,7 @@ pub struct Store {
 	db: Arc<RwLock<Option<Arc<lmdb::Database<'static>>>>>,
 	name: String,
 	version: ProtocolVersion,
+	alloc_chunk_size: usize,
 }
 
 impl Store {
@@ -105,6 +109,11 @@ impl Store {
 			env_builder.set_maxreaders(max_readers)?;
 		}
 
+		let alloc_chunk_size = match global::is_production_mode() {
+			true => ALLOC_CHUNK_SIZE_DEFAULT,
+			false => ALLOC_CHUNK_SIZE_DEFAULT_TEST,
+		};
+
 		let env = unsafe { env_builder.open(&full_path, lmdb::open::NOTLS, 0o600)? };
 
 		debug!(
@@ -117,6 +126,7 @@ impl Store {
 			db: Arc::new(RwLock::new(None)),
 			name: db_name,
 			version: DEFAULT_DB_VERSION,
+			alloc_chunk_size,
 		};
 
 		{
@@ -133,11 +143,16 @@ impl Store {
 	/// Construct a new store using a specific protocol version.
 	/// Permits access to the db with legacy protocol versions for db migrations.
 	pub fn with_version(&self, version: ProtocolVersion) -> Store {
+		let alloc_chunk_size = match global::is_production_mode() {
+			true => ALLOC_CHUNK_SIZE_DEFAULT,
+			false => ALLOC_CHUNK_SIZE_DEFAULT_TEST,
+		};
 		Store {
 			env: self.env.clone(),
 			db: self.db.clone(),
 			name: self.name.clone(),
 			version: version,
+			alloc_chunk_size,
 		}
 	}
 
@@ -171,7 +186,7 @@ impl Store {
 		);
 
 		if size_used as f32 / env_info.mapsize as f32 > resize_percent
-			|| env_info.mapsize < ALLOC_CHUNK_SIZE
+			|| env_info.mapsize < self.alloc_chunk_size
 		{
 			trace!("Resize threshold met (percent-based)");
 			Ok(true)
@@ -188,12 +203,12 @@ impl Store {
 		let stat = self.env.stat()?;
 		let size_used = stat.psize as usize * env_info.last_pgno;
 
-		let new_mapsize = if env_info.mapsize < ALLOC_CHUNK_SIZE {
-			ALLOC_CHUNK_SIZE
+		let new_mapsize = if env_info.mapsize < self.alloc_chunk_size {
+			self.alloc_chunk_size
 		} else {
 			let mut tot = env_info.mapsize;
 			while size_used as f32 / tot as f32 > RESIZE_MIN_TARGET_PERCENT {
-				tot += ALLOC_CHUNK_SIZE;
+				tot += self.alloc_chunk_size;
 			}
 			tot
 		};
diff --git a/store/tests/lmdb.rs b/store/tests/lmdb.rs
index 5f072567a..0f37916cb 100644
--- a/store/tests/lmdb.rs
+++ b/store/tests/lmdb.rs
@@ -20,7 +20,7 @@ use grin_core::ser::{self, Readable, Reader, Writeable, Writer};
 use std::fs;
 
 const WRITE_CHUNK_SIZE: usize = 20;
-const TEST_ALLOC_SIZE: usize = store::lmdb::ALLOC_CHUNK_SIZE / 8 / WRITE_CHUNK_SIZE;
+const TEST_ALLOC_SIZE: usize = store::lmdb::ALLOC_CHUNK_SIZE_DEFAULT / 8 / WRITE_CHUNK_SIZE;
 
 #[derive(Clone)]
 struct PhatChunkStruct {