Allow fallocate_reserve to be a percentage

Add the ability to set the fallocate_reserve value as a percentage.
This happens automatically when adding the '%' at the end of the value.
Having the ability to set a % of free space rather than a byte value is
useful especially when drive sizes are heterogenous.

The default for fallocate_reserve has been adjusted to 1%, having the
fallocate_reserve set seems sensible for all deploys and percentages are
far safer to default than byte values (across drives of any size).

Tests added for using fallocate_reserve as a percentage.

Duplicate tests for fallocate_reserve have been removed.

Docs updated to reflect the fallocate_reserve change.

Change-Id: I4aea613a708205c917e81d6b2861396655e73238

doc/manpages/account-server.conf.5

@@ -121,8 +121,10 @@ The default is false.
 .IP \fBeventlet_debug\fR
 Debug mode for eventlet library. The default is false.
 .IP \fBfallocate_reserve\fR
-You can set fallocate_reserve to the number of bytes you'd like fallocate to
+You can set fallocate_reserve to the number of bytes or percentage of disk
-reserve, whether there is space for the given file size or not. The default is 0.
+space you'd like fallocate to reserve, whether there is space for the given
+file size or not. Percentage will be used if the value ends with a '%'.
+The default is 1%.
 .RE
 .PD
 

doc/manpages/container-server.conf.5

@@ -127,8 +127,10 @@ The default is false.
 .IP \fBeventlet_debug\fR
 Debug mode for eventlet library. The default is false.
 .IP \fBfallocate_reserve\fR
-You can set fallocate_reserve to the number of bytes you'd like fallocate to
+You can set fallocate_reserve to the number of bytes or percentage of disk
-reserve, whether there is space for the given file size or not. The default is 0.
+space you'd like fallocate to reserve, whether there is space for the given
+file size or not. Percentage will be used if the value ends with a '%'.
+The default is 1%.
 .RE
 .PD
 

doc/manpages/object-server.conf.5

@@ -126,8 +126,10 @@ The default is empty.
 .IP \fBeventlet_debug\fR
 Debug mode for eventlet library. The default is false.
 .IP \fBfallocate_reserve\fR
-You can set fallocate_reserve to the number of bytes you'd like fallocate to
+You can set fallocate_reserve to the number of bytes or percentage of disk
-reserve, whether there is space for the given file size or not. The default is 0.
+space you'd like fallocate to reserve, whether there is space for the given
+file size or not. Percentage will be used if the value ends with a '%'.
+The default is 1%.
 .IP \fBnode_timeout\fR
 Request timeout to external services. The default is 3 seconds.
 .IP \fBconn_timeout\fR

doc/source/deployment_guide.rst

@@ -489,12 +489,14 @@ log_statsd_sample_rate_factor    1.0
 log_statsd_metric_prefix
 eventlet_debug                   false       If true, turn on debug logging for
                                              eventlet
-fallocate_reserve                0           You can set fallocate_reserve to the
+fallocate_reserve                1%          You can set fallocate_reserve to the
-                                             number of bytes you'd like fallocate to
+                                             number of bytes or percentage of disk
-                                             reserve, whether there is space for the
+                                             space you'd like fallocate to reserve,
-                                             given file size or not. This is useful for
+                                             whether there is space for the given
-                                             systems that behave badly when they
+                                             file size or not. Percentage will be used
-                                             completely run out of space; you can
+                                             if the value ends with a '%'. This is
+                                             useful for systems that behave badly when
+                                             they completely run out of space; you can
                                              make the services pretend they're out of
                                              space early.
 conn_timeout                     0.5         Time to wait while attempting to connect
@@ -809,13 +811,16 @@ log_statsd_default_sample_rate   1.0
 log_statsd_sample_rate_factor    1.0
 log_statsd_metric_prefix
 eventlet_debug                   false       If true, turn on debug logging for eventlet
-fallocate_reserve                0           You can set fallocate_reserve to the number of
+fallocate_reserve                1%          You can set fallocate_reserve to the
-                                             bytes you'd like fallocate to reserve, whether
+                                             number of bytes or percentage of disk
-                                             there is space for the given file size or not.
+                                             space you'd like fallocate to reserve,
-                                             This is useful for systems that behave badly
+                                             whether there is space for the given
-                                             when they completely run out of space; you can
+                                             file size or not. Percentage will be used
-                                             make the services pretend they're out of space
+                                             if the value ends with a '%'. This is
-                                             early.
+                                             useful for systems that behave badly when
+                                             they completely run out of space; you can
+                                             make the services pretend they're out of
+                                             space early.
 db_preallocation                 off         If you don't mind the extra disk space usage
                                              in overhead, you can turn this on to preallocate
                                              disk space with SQLite databases to decrease
@@ -1024,13 +1029,16 @@ log_statsd_default_sample_rate   1.0
 log_statsd_sample_rate_factor    1.0
 log_statsd_metric_prefix
 eventlet_debug                   false       If true, turn on debug logging for eventlet
-fallocate_reserve                0           You can set fallocate_reserve to the number of
+fallocate_reserve                1%          You can set fallocate_reserve to the
-                                             bytes you'd like fallocate to reserve, whether
+                                             number of bytes or percentage of disk
-                                             there is space for the given file size or not.
+                                             space you'd like fallocate to reserve,
-                                             This is useful for systems that behave badly
+                                             whether there is space for the given
-                                             when they completely run out of space; you can
+                                             file size or not. Percentage will be used
-                                             make the services pretend they're out of space
+                                             if the value ends with a '%'. This is
-                                             early.
+                                             useful for systems that behave badly when
+                                             they completely run out of space; you can
+                                             make the services pretend they're out of
+                                             space early.
 ===============================  ==========  =============================================
 
 [account-server]

etc/account-server.conf-sample

@@ -47,9 +47,10 @@ bind_port = 6002
 #
 # eventlet_debug = false
 #
-# You can set fallocate_reserve to the number of bytes you'd like fallocate to
+# You can set fallocate_reserve to the number of bytes or percentage of disk
-# reserve, whether there is space for the given file size or not.
+# space you'd like fallocate to reserve, whether there is space for the given
-# fallocate_reserve = 0
+# file size or not. Percentage will be used if the value ends with a '%'.
+# fallocate_reserve = 1%
 
 [pipeline:main]
 pipeline = healthcheck recon account-server

etc/container-server.conf-sample

@@ -53,9 +53,10 @@ bind_port = 6001
 #
 # eventlet_debug = false
 #
-# You can set fallocate_reserve to the number of bytes you'd like fallocate to
+# You can set fallocate_reserve to the number of bytes or percentage of disk
-# reserve, whether there is space for the given file size or not.
+# space you'd like fallocate to reserve, whether there is space for the given
-# fallocate_reserve = 0
+# file size or not. Percentage will be used if the value ends with a '%'.
+# fallocate_reserve = 1%
 
 [pipeline:main]
 pipeline = healthcheck recon container-server

etc/object-server.conf-sample

@@ -52,9 +52,10 @@ bind_port = 6000
 #
 # eventlet_debug = false
 #
-# You can set fallocate_reserve to the number of bytes you'd like fallocate to
+# You can set fallocate_reserve to the number of bytes or percentage of disk
-# reserve, whether there is space for the given file size or not.
+# space you'd like fallocate to reserve, whether there is space for the given
-# fallocate_reserve = 0
+# file size or not. Percentage will be used if the value ends with a '%'.
+# fallocate_reserve = 1%
 #
 # Time to wait while attempting to connect to another backend node.
 # conn_timeout = 0.5

swift/common/daemon.py

@@ -92,9 +92,8 @@ def run_daemon(klass, conf_file, section_name='', once=False, **kwargs):
     if utils.config_true_value(conf.get('disable_fallocate', 'no')):
         utils.disable_fallocate()
     # set utils.FALLOCATE_RESERVE if desired
-    reserve = int(conf.get('fallocate_reserve', 0))
+    utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
-    if reserve > 0:
+        utils.config_fallocate_value(conf.get('fallocate_reserve', '1%'))
-        utils.FALLOCATE_RESERVE = reserve
 
     # By default, disable eventlet printing stacktraces
     eventlet_debug = utils.config_true_value(conf.get('eventlet_debug', 'no'))

swift/common/utils.py

@@ -97,6 +97,9 @@ _libc_accept = None
 # If set to non-zero, fallocate routines will fail based on free space
 # available being at or below this amount, in bytes.
 FALLOCATE_RESERVE = 0
+# Indicates if FALLOCATE_RESERVE is the percentage of free space (True) or
+# the number of bytes (False).
+FALLOCATE_IS_PERCENT = False
 
 # Used by hash_path to offer a bit more security when generating hashes for
 # paths. It simply appends this value to all paths; guessing the hash a path
@@ -453,6 +456,25 @@ def get_trans_id_time(trans_id):
     return None
 
 
+def config_fallocate_value(reserve_value):
+    """
+    Returns fallocate reserve_value as an int or float.
+    Returns is_percent as a boolean.
+    Returns a ValueError on invalid fallocate value.
+    """
+    try:
+        if str(reserve_value[-1:]) == '%':
+            reserve_value = float(reserve_value[:-1])
+            is_percent = True
+        else:
+            reserve_value = int(reserve_value)
+            is_percent = False
+    except ValueError:
+        raise ValueError('Error: %s is an invalid value for fallocate'
+                         '_reserve.' % reserve_value)
+    return reserve_value, is_percent
+
+
 class FileLikeIter(object):
 
     def __init__(self, iterable):
@@ -596,7 +618,9 @@ class FallocateWrapper(object):
         if FALLOCATE_RESERVE > 0:
             st = os.fstatvfs(fd)
             free = st.f_frsize * st.f_bavail - length.value
-            if free <= FALLOCATE_RESERVE:
+            if FALLOCATE_IS_PERCENT:
+                free = (float(free) / float(st.f_frsize * st.f_blocks)) * 100
+            if float(free) <= float(FALLOCATE_RESERVE):
                 raise OSError(
                     errno.ENOSPC,
                     'FALLOCATE_RESERVE fail %s <= %s' % (free,

swift/common/wsgi.py

@@ -897,9 +897,9 @@ def run_wsgi(conf_path, app_section, *args, **kwargs):
     loadapp(conf_path, global_conf=global_conf)
 
     # set utils.FALLOCATE_RESERVE if desired
-    reserve = int(conf.get('fallocate_reserve', 0))
+    utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
-    if reserve > 0:
+        utils.config_fallocate_value(conf.get('fallocate_reserve', '1%'))
-        utils.FALLOCATE_RESERVE = reserve
+
     # redirect errors to logger and close stdio
     capture_stdio(logger)
 

test/unit/common/test_utils.py

@@ -2583,6 +2583,7 @@ cluster_dfw1 = http://dfw1.host/v1/
         class StatVFS(object):
             f_frsize = 1024
             f_bavail = 1
+            f_blocks = 100
 
         def fstatvfs(fd):
             return StatVFS()
@@ -2593,17 +2594,20 @@ cluster_dfw1 = http://dfw1.host/v1/
             fallocate = utils.FallocateWrapper(noop=True)
             utils.os.fstatvfs = fstatvfs
             # Want 1023 reserved, have 1024 * 1 free, so succeeds
-            utils.FALLOCATE_RESERVE = 1023
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('1023')
             StatVFS.f_frsize = 1024
             StatVFS.f_bavail = 1
             self.assertEqual(fallocate(0, 1, 0, ctypes.c_uint64(0)), 0)
             # Want 1023 reserved, have 512 * 2 free, so succeeds
-            utils.FALLOCATE_RESERVE = 1023
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('1023')
             StatVFS.f_frsize = 512
             StatVFS.f_bavail = 2
             self.assertEqual(fallocate(0, 1, 0, ctypes.c_uint64(0)), 0)
             # Want 1024 reserved, have 1024 * 1 free, so fails
-            utils.FALLOCATE_RESERVE = 1024
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('1024')
             StatVFS.f_frsize = 1024
             StatVFS.f_bavail = 1
             exc = None
@@ -2615,7 +2619,8 @@ cluster_dfw1 = http://dfw1.host/v1/
                              '[Errno 28] FALLOCATE_RESERVE fail 1024 <= 1024')
             self.assertEqual(err.errno, errno.ENOSPC)
             # Want 1024 reserved, have 512 * 2 free, so fails
-            utils.FALLOCATE_RESERVE = 1024
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('1024')
             StatVFS.f_frsize = 512
             StatVFS.f_bavail = 2
             exc = None
@@ -2627,7 +2632,8 @@ cluster_dfw1 = http://dfw1.host/v1/
                              '[Errno 28] FALLOCATE_RESERVE fail 1024 <= 1024')
             self.assertEqual(err.errno, errno.ENOSPC)
             # Want 2048 reserved, have 1024 * 1 free, so fails
-            utils.FALLOCATE_RESERVE = 2048
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('2048')
             StatVFS.f_frsize = 1024
             StatVFS.f_bavail = 1
             exc = None
@@ -2639,7 +2645,8 @@ cluster_dfw1 = http://dfw1.host/v1/
                              '[Errno 28] FALLOCATE_RESERVE fail 1024 <= 2048')
             self.assertEqual(err.errno, errno.ENOSPC)
             # Want 2048 reserved, have 512 * 2 free, so fails
-            utils.FALLOCATE_RESERVE = 2048
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('2048')
             StatVFS.f_frsize = 512
             StatVFS.f_bavail = 2
             exc = None
@@ -2652,7 +2659,8 @@ cluster_dfw1 = http://dfw1.host/v1/
             self.assertEqual(err.errno, errno.ENOSPC)
             # Want 1023 reserved, have 1024 * 1 free, but file size is 1, so
             # fails
-            utils.FALLOCATE_RESERVE = 1023
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('1023')
             StatVFS.f_frsize = 1024
             StatVFS.f_bavail = 1
             exc = None
@@ -2665,28 +2673,95 @@ cluster_dfw1 = http://dfw1.host/v1/
             self.assertEqual(err.errno, errno.ENOSPC)
             # Want 1022 reserved, have 1024 * 1 free, and file size is 1, so
             # succeeds
-            utils.FALLOCATE_RESERVE = 1022
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('1022')
             StatVFS.f_frsize = 1024
             StatVFS.f_bavail = 1
             self.assertEqual(fallocate(0, 1, 0, ctypes.c_uint64(1)), 0)
-            # Want 1023 reserved, have 1024 * 1 free, and file size is 0, so
+            # Want 1% reserved, have 100 bytes * 2/100 free, and file size is
-            # succeeds
+            # 99, so succeeds
-            utils.FALLOCATE_RESERVE = 1023
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
-            StatVFS.f_frsize = 1024
+                utils.config_fallocate_value('1%')
-            StatVFS.f_bavail = 1
+            StatVFS.f_frsize = 100
-            self.assertEqual(fallocate(0, 1, 0, ctypes.c_uint64(0)), 0)
+            StatVFS.f_bavail = 2
-            # Want 1024 reserved, have 1024 * 1 free, and even though
+            StatVFS.f_blocks = 100
-            # file size is 0, since we're under the reserve, fails
+            self.assertEqual(fallocate(0, 1, 0, ctypes.c_uint64(99)), 0)
-            utils.FALLOCATE_RESERVE = 1024
+            # Want 2% reserved, have 50 bytes * 2/50 free, and file size is 49,
-            StatVFS.f_frsize = 1024
+            # so succeeds
-            StatVFS.f_bavail = 1
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('2%')
+            StatVFS.f_frsize = 50
+            StatVFS.f_bavail = 2
+            StatVFS.f_blocks = 50
+            self.assertEqual(fallocate(0, 1, 0, ctypes.c_uint64(49)), 0)
+            # Want 100% reserved, have  100 * 100/100 free, and file size is 0,
+            # so fails.
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('100%')
+            StatVFS.f_frsize = 100
+            StatVFS.f_bavail = 100
+            StatVFS.f_blocks = 100
             exc = None
             try:
                 fallocate(0, 1, 0, ctypes.c_uint64(0))
             except OSError as err:
                 exc = err
             self.assertEqual(str(exc),
-                             '[Errno 28] FALLOCATE_RESERVE fail 1024 <= 1024')
+                             '[Errno 28] FALLOCATE_RESERVE fail 100.0 <= '
+                             '100.0')
+            self.assertEqual(err.errno, errno.ENOSPC)
+            # Want 1% reserved, have 100 * 2/100 free, and file size is 101,
+            # so fails.
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('1%')
+            StatVFS.f_frsize = 100
+            StatVFS.f_bavail = 2
+            StatVFS.f_blocks = 100
+            exc = None
+            try:
+                fallocate(0, 1, 0, ctypes.c_uint64(101))
+            except OSError as err:
+                exc = err
+            self.assertEqual(str(exc),
+                             '[Errno 28] FALLOCATE_RESERVE fail 0.99 <= 1.0')
+            self.assertEqual(err.errno, errno.ENOSPC)
+            # Want 98% reserved, have 100 bytes * 99/100 free, and file size
+            # is 100, so fails
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('98%')
+            StatVFS.f_frsize = 100
+            StatVFS.f_bavail = 99
+            StatVFS.f_blocks = 100
+            exc = None
+            try:
+                fallocate(0, 1, 0, ctypes.c_uint64(100))
+            except OSError as err:
+                exc = err
+            self.assertEqual(str(exc),
+                             '[Errno 28] FALLOCATE_RESERVE fail 98.0 <= 98.0')
+            self.assertEqual(err.errno, errno.ENOSPC)
+            # Want 2% reserved, have 1000 bytes * 21/1000 free, and file size
+            # is 999, so succeeds.
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('2%')
+            StatVFS.f_frsize = 1000
+            StatVFS.f_bavail = 21
+            StatVFS.f_blocks = 1000
+            self.assertEqual(fallocate(0, 1, 0, ctypes.c_uint64(999)), 0)
+            # Want 2% resereved, have 1000 bytes * 21/1000 free, and file size
+            # is 1000, so fails.
+            utils.FALLOCATE_RESERVE, utils.FALLOCATE_IS_PERCENT = \
+                utils.config_fallocate_value('2%')
+            StatVFS.f_frsize = 1000
+            StatVFS.f_bavail = 21
+            StatVFS.f_blocks = 1000
+            exc = None
+            try:
+                fallocate(0, 1, 0, ctypes.c_uint64(1000))
+            except OSError as err:
+                exc = err
+            self.assertEqual(str(exc),
+                             '[Errno 28] FALLOCATE_RESERVE fail 2.0 <= 2.0')
             self.assertEqual(err.errno, errno.ENOSPC)
         finally:
             utils.FALLOCATE_RESERVE = orig_FALLOCATE_RESERVE
@@ -2767,6 +2842,44 @@ cluster_dfw1 = http://dfw1.host/v1/
         ts = utils.get_trans_id_time('tx1df4ff4f55ea45f7b2ec2-almostright')
         self.assertEqual(ts, None)
 
+    def test_config_fallocate_value(self):
+        fallocate_value, is_percent = utils.config_fallocate_value('10%')
+        self.assertEqual(fallocate_value, 10)
+        self.assertTrue(is_percent)
+        fallocate_value, is_percent = utils.config_fallocate_value('10')
+        self.assertEqual(fallocate_value, 10)
+        self.assertFalse(is_percent)
+        try:
+            fallocate_value, is_percent = utils.config_fallocate_value('ab%')
+        except ValueError as err:
+            exc = err
+        self.assertEqual(str(exc), 'Error: ab% is an invalid value for '
+                                   'fallocate_reserve.')
+        try:
+            fallocate_value, is_percent = utils.config_fallocate_value('ab')
+        except ValueError as err:
+            exc = err
+        self.assertEqual(str(exc), 'Error: ab is an invalid value for '
+                                   'fallocate_reserve.')
+        try:
+            fallocate_value, is_percent = utils.config_fallocate_value('1%%')
+        except ValueError as err:
+            exc = err
+        self.assertEqual(str(exc), 'Error: 1%% is an invalid value for '
+                                   'fallocate_reserve.')
+        try:
+            fallocate_value, is_percent = utils.config_fallocate_value('10.0')
+        except ValueError as err:
+            exc = err
+        self.assertEqual(str(exc), 'Error: 10.0 is an invalid value for '
+                                   'fallocate_reserve.')
+        fallocate_value, is_percent = utils.config_fallocate_value('10.5%')
+        self.assertEqual(fallocate_value, 10.5)
+        self.assertTrue(is_percent)
+        fallocate_value, is_percent = utils.config_fallocate_value('10.000%')
+        self.assertEqual(fallocate_value, 10.000)
+        self.assertTrue(is_percent)
+
     def test_tpool_reraise(self):
         with patch.object(utils.tpool, 'execute', lambda f: f()):
             self.assertTrue(