Adding RAID 5+0 support, memory fixes and improovements for big disks

1 files changed, 33 insertions, 5 deletions

diff --git a/myraid.py b/myraid.py
index 75402d9..4a6ad6a 100644
--- a/myraid.py
+++ b/myraid.py
@@ -79,6 +79,7 @@ class MyRaid():
         self.raid_disk_count = 0
         self.raid_layout = 'ls'
         self.raid_disks = []
+        self.nested_subraid = 2
 
     def get_raid_start(self):
         return self.raid_start
@@ -182,7 +183,7 @@ class MyRaid():
         if raid_type in ['1','5', '5+0']:
             result = ''.join(
                     [ '0x%011x %c\n'%( addr, MyRaid.xor_blocks(self.raid_disks, addr, self.raid_sector_size)[0])
-                            for addr in range(start, end, self.raid_sector_size)
+                            for addr in xrange(start, end, self.raid_sector_size)
                     ])
         else:
             result = None
@@ -195,7 +196,7 @@ class MyRaid():
         """Returns actual RAID data"""
         if raid_type == '0':
             segment_no = offset / self.raid_chunk_size
-            segment_off = offset % self.raid_chunk_size 
+            segment_off = offset % self.raid_chunk_size
             stripe_no = segment_no / self.raid_disk_count
             par_disk = -1
             data_disk = segment_no % self.raid_disk_count
@@ -213,7 +214,7 @@ class MyRaid():
 
         elif raid_type == '5':
             segment_no = offset / self.raid_chunk_size
-            segment_off = offset % self.raid_chunk_size 
+            segment_off = offset % self.raid_chunk_size
             stripe_no = segment_no / (self.raid_disk_count-1)
 
             if self.raid_layout in ['ls','la']:
@@ -229,8 +230,35 @@ class MyRaid():
                     data_disk = data_disk + 1
 
             off_disk = self.raid_start + stripe_no * self.raid_chunk_size + segment_off
-            # Note : self make shorter read than asked but convince the reader to be chunck aligned, which is great
+            # Note : could make error-free shorter reads than asked but convince the reader to be chunck aligned, which is great for perf
             size2 = min(size, (segment_no+1) * self.raid_chunk_size - offset)
+
+        elif raid_type == '5+0':
+            subraid_disk_count = self.raid_disk_count / self.nested_subraid
+            segment_no = offset / self.raid_chunk_size
+            segment_off = offset % self.raid_chunk_size
+            stripe_no = segment_no / (self.raid_disk_count - self.nested_subraid)                # segment_no / 12
+            subraid_no = (segment_no / (subraid_disk_count-1) ) % self.nested_subraid            # (segment_no/6) mod 2
+
+            if self.raid_layout in ['ls','la']:
+                subraid_par_disk = (subraid_disk_count-1) - (stripe_no % subraid_disk_count)
+            else: # self.raid_layout in ['rs','ra']:
+                subraid_par_disk = stripe_no % subraid_disk_count
+
+            if self.raid_layout in ['ls','rs']:
+                subraid_data_disk = (subraid_par_disk+1 + (segment_no % (subraid_disk_count-1)) ) % subraid_disk_count
+            else: # self.raid_layout in ['la','ra']:
+                subraid_data_disk = segment_no % (subraid_disk_count-1)
+                if subraid_data_disk >= subraid_par_disk:
+                    subraid_data_disk = subraid_data_disk + 1
+
+            par_disk  = subraid_no * subraid_disk_count + subraid_par_disk
+            data_disk = subraid_no * subraid_disk_count + subraid_data_disk
+
+            off_disk = self.raid_start + stripe_no * self.raid_chunk_size + segment_off
+            # Note : could make error-free shorter reads than asked but convince the reader to be chunck aligned, which is great for perf
+            size2 = min(size, (segment_no+1) * self.raid_chunk_size - offset)
+
         else:
             raise Exception('Unimplemented read_raid_result() for raid_type == %s', raid_type)
 
@@ -253,7 +281,7 @@ class MyRaid():
             other_fds.remove(data_fd)
 
             data_arr = []
-            for s in range(off_disk, off_disk+size2, self.raid_sector_size):
+            for s in xrange(off_disk, off_disk+size2, self.raid_sector_size):
                 if self.d.is_readable(self.raid_disk_order[data_disk],s,self.raid_sector_size):
                     # Current sector is readable from data disk, read it
                     logging.debug('-> 0x%011x : readable'%s)