Neil,
The write behind value does not get converted to/from little endian
which causes write behind not to work on big endian machines (RUN ARRAY
fails with invalid argument error):
# mdadm -B /dev/md0 -l1 -n2 --write-behind=256 /dev/sdb10 --write-mostly
/dev/nbd0 --bitmap=/bitmaps/test5
mdadm: RUN_ARRAY failed: Invalid argument
# tail /var/log/messages
Oct 6 13:14:48 caspian kernel: daemon sleep: 5s
Oct 6 13:14:48 caspian kernel: sync size: 1001456 KB
Oct 6 13:14:48 caspian kernel: max write behind: 65536
Oct 6 13:14:48 caspian kernel: md0: failed to create bitmap (-22)
Attached patch for mdadm fixes this.
Thanks,
Paul
--- mdadm-2.5.1/bitmap.c.orig Fri Oct 6 13:40:35 2006
+++ mdadm-2.5.1/bitmap.c Fri Oct 6 13:40:53 2006
@@ -33,6 +33,7 @@ inline void sb_le_to_cpu(bitmap_super_t
sb->chunksize = __le32_to_cpu(sb->chunksize);
sb->daemon_sleep = __le32_to_cpu(sb->daemon_sleep);
sb->sync_size = __le64_to_cpu(sb->sync_size);
+ sb->write_behind = __le32_to_cpu(sb->sync_size);
}
inline void sb_cpu_to_le(bitmap_super_t *sb)
