diff --git a/tosfs/consts.py b/tosfs/consts.py
index fc82585..31ef130 100644
--- a/tosfs/consts.py
+++ b/tosfs/consts.py
@@ -27,8 +27,19 @@
     "ServiceUnavailable",
 }
 
-MANAGED_COPY_THRESHOLD = 5 * 2**30
+MANAGED_COPY_MAX_THRESHOLD = 5 * 2**30
+MANAGED_COPY_MIN_THRESHOLD = 5 * 2**20
 
 RETRY_NUM = 5
 PART_MIN_SIZE = 5 * 2**20
 PART_MAX_SIZE = 5 * 2**30
+
+FILE_OPERATION_READ_WRITE_BUFFER_SIZE = 5 * 2**20  # 5MB
+PUT_OBJECT_OPERATION_SMALL_FILE_THRESHOLD = 5 * 2**30  # 5GB
+GET_OBJECT_OPERATION_DEFAULT_READ_CHUNK_SIZE = 2**16  # 64KB
+APPEND_OPERATION_SMALL_FILE_THRESHOLD = 5 * 2**20  # 5MB
+
+LS_OPERATION_DEFAULT_MAX_ITEMS = 1000
+
+# environment variable names
+ENV_NAME_TOSFS_LOGGING_LEVEL = "TOSFS_LOGGING_LEVEL"
diff --git a/tosfs/core.py b/tosfs/core.py
index 34f6857..f74f117 100644
--- a/tosfs/core.py
+++ b/tosfs/core.py
@@ -35,8 +35,15 @@
 )
 
 from tosfs.consts import (
-    MANAGED_COPY_THRESHOLD,
+    APPEND_OPERATION_SMALL_FILE_THRESHOLD,
+    ENV_NAME_TOSFS_LOGGING_LEVEL,
+    FILE_OPERATION_READ_WRITE_BUFFER_SIZE,
+    GET_OBJECT_OPERATION_DEFAULT_READ_CHUNK_SIZE,
+    LS_OPERATION_DEFAULT_MAX_ITEMS,
+    MANAGED_COPY_MAX_THRESHOLD,
+    MANAGED_COPY_MIN_THRESHOLD,
     PART_MAX_SIZE,
+    PUT_OBJECT_OPERATION_SMALL_FILE_THRESHOLD,
     RETRY_NUM,
     TOS_SERVER_RESPONSE_CODE_NOT_FOUND,
 )
@@ -44,9 +51,6 @@
 from tosfs.fsspec_utils import glob_translate
 from tosfs.utils import find_bucket_key, get_brange, retryable_func_wrapper
 
-# environment variable names
-ENV_NAME_TOSFS_LOGGING_LEVEL = "TOSFS_LOGGING_LEVEL"
-
 logger = logging.getLogger("tosfs")
 
 
@@ -73,7 +77,6 @@ class TosFileSystem(AbstractFileSystem):
     """
 
     protocol = ("tos", "tosfs")
-    default_block_size = 5 * 2**20
 
     def __init__(
         self,
@@ -97,7 +100,9 @@ def __init__(
             credentials_provider=credentials_provider,
         )
         self.version_aware = version_aware
-        self.default_block_size = default_block_size or self.default_block_size
+        self.default_block_size = (
+            default_block_size or FILE_OPERATION_READ_WRITE_BUFFER_SIZE
+        )
         self.default_fill_cache = default_fill_cache
         self.default_cache_type = default_cache_type
 
@@ -519,7 +524,7 @@ def put_file(
         self,
         lpath: str,
         rpath: str,
-        chunksize: int = 5 * 2**20,
+        chunksize: int = FILE_OPERATION_READ_WRITE_BUFFER_SIZE,
         **kwargs: Any,
     ) -> None:
         """Put a file from local to TOS.
@@ -578,7 +583,7 @@ def put_file(
             bucket, key, _ = self._split_path(rpath)
 
             with open(lpath, "rb") as f:
-                if size < min(5 * 2**30, 2 * chunksize):
+                if size < min(PUT_OBJECT_OPERATION_SMALL_FILE_THRESHOLD, 2 * chunksize):
                     chunk = f.read()
                     self.tos_client.put_object(
                         bucket,
@@ -642,10 +647,10 @@ def _read_chunks(body: BinaryIO, f: BinaryIO) -> None:
             bytes_read = 0
             while True:
                 try:
-                    chunk = body.read(2**16)
+                    chunk = body.read(GET_OBJECT_OPERATION_DEFAULT_READ_CHUNK_SIZE)
                 except tos.exceptions.TosClientError as e:
                     failed_reads += 1
-                    if failed_reads >= self.RETRY_NUM:
+                    if failed_reads >= RETRY_NUM:
                         raise e
                     try:
                         body.close()
@@ -848,7 +853,7 @@ def cp_file(
         path1: str,
         path2: str,
         preserve_etag: Optional[bool] = None,
-        managed_copy_threshold: Optional[int] = MANAGED_COPY_THRESHOLD,
+        managed_copy_threshold: Optional[int] = MANAGED_COPY_MAX_THRESHOLD,
         **kwargs: Any,
     ) -> None:
         """Copy file between locations on tos.
@@ -897,11 +902,11 @@ def cp_file(
         if preserve_etag and parts_suffix:
             self._copy_etag_preserved(path1, path2, size, total_parts=int(parts_suffix))
         elif size <= min(
-            MANAGED_COPY_THRESHOLD,
+            MANAGED_COPY_MAX_THRESHOLD,
             (
                 managed_copy_threshold
                 if managed_copy_threshold
-                else MANAGED_COPY_THRESHOLD
+                else MANAGED_COPY_MAX_THRESHOLD
             ),
         ):
             self._copy_basic(path1, path2, **kwargs)
@@ -1065,17 +1070,17 @@ def _copy_managed(
         path1: str,
         path2: str,
         size: int,
-        block: int = MANAGED_COPY_THRESHOLD,
+        block: int = MANAGED_COPY_MAX_THRESHOLD,
         **kwargs: Any,
     ) -> None:
         """Copy file between locations on tos as multiple-part.
 
         block: int
             The size of the pieces, must be larger than 5MB and at
-            most MANAGED_COPY_THRESHOLD.
+            most MANAGED_COPY_MAX_THRESHOLD.
             Smaller blocks mean more calls, only useful for testing.
         """
-        if block < 5 * 2**20 or block > MANAGED_COPY_THRESHOLD:
+        if block < MANAGED_COPY_MIN_THRESHOLD or block > MANAGED_COPY_MAX_THRESHOLD:
             raise ValueError("Copy block size must be 5MB<=block<=5GB")
 
         bucket1, key1, version1 = self._split_path(path1)
@@ -1485,7 +1490,7 @@ def _lsbuckets(self) -> List[dict]:
     def _lsdir(
         self,
         path: str,
-        max_items: int = 1000,
+        max_items: int = LS_OPERATION_DEFAULT_MAX_ITEMS,
         delimiter: str = "/",
         prefix: str = "",
         include_self: bool = False,
@@ -1555,7 +1560,7 @@ def _lsdir(
     def _listdir(
         self,
         bucket: str,
-        max_items: int = 1000,
+        max_items: int = LS_OPERATION_DEFAULT_MAX_ITEMS,
         delimiter: str = "/",
         prefix: str = "",
         include_self: bool = False,
@@ -1779,7 +1784,7 @@ def __init__(
             head = self.fs.tos_client.head_object(bucket, key)
             loc = head.content_length
 
-            if loc < 5 * 2**20:
+            if loc < APPEND_OPERATION_SMALL_FILE_THRESHOLD:
                 # existing file too small for multi-upload: download
                 self.write(self.fs.cat(self.path))
             else: