Data lost in MySQL InnoDB after crash

Question

I found a 6-days rollback in a MySQL 5.6 community edition server installation. It seems that some logs were lost, and I cannot understand why.

2013-12-22 20:38:54 380 [Note] Plugin 'FEDERATED' is disabled.
2013-12-22 20:38:54 380 [Warning] option 'innodb-autoextend-increment': unsigned value 67108864 adjusted to 1000
2013-12-22 20:38:54 388 InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed in future releases, together with the option innodb_use_sys_malloc and with the InnoDB's internal memory allocator.
2013-12-22 20:38:54 380 [Note] InnoDB: The InnoDB memory heap is disabled
2013-12-22 20:38:54 380 [Note] InnoDB: Mutexes and rw_locks use Windows interlocked functions
2013-12-22 20:38:54 380 [Note] InnoDB: Compressed tables use zlib 1.2.3
2013-12-22 20:38:54 380 [Note] InnoDB: Not using CPU crc32 instructions
2013-12-22 20:38:54 380 [Note] InnoDB: Initializing buffer pool, size = 86.0M
2013-12-22 20:38:54 380 [Note] InnoDB: Completed initialization of buffer pool
2013-12-22 20:38:54 380 [Note] InnoDB: Highest supported file format is Barracuda.
2013-12-22 20:38:54 380 [Note] InnoDB: The log sequence numbers 5988825 and 5988825 in ibdata files do not match the log sequence number 6057379 in the ib_logfiles!
2013-12-22 20:38:54 380 [Note] InnoDB: Database was not shutdown normally!
2013-12-22 20:38:54 380 [Note] InnoDB: Starting crash recovery.
2013-12-22 20:38:54 380 [Note] InnoDB: Reading tablespace information from the .ibd files...
2013-12-22 20:38:57 380 [Note] InnoDB: Restoring possible half-written data pages 
2013-12-22 20:38:57 380 [Note] InnoDB: from the doublewrite buffer...
2013-12-22 20:39:07 380 [Note] InnoDB: 128 rollback segment(s) are active.
2013-12-22 20:39:07 380 [Note] InnoDB: Waiting for purge to start
2013-12-22 20:39:07 380 [Note] InnoDB: 5.6.13 started; log sequence number 6057379
2013-12-22 20:39:07 380 [Note] Server hostname (bind-address): '*'; port: 3306
2013-12-22 20:39:07 380 [Note] IPv6 is available.
2013-12-22 20:39:07 380 [Note]   - '::' resolves to '::';
2013-12-22 20:39:07 380 [Note] Server socket created on IP: '::'.
2013-12-22 20:39:12 380 [Note] Event Scheduler: Loaded 0 events
2013-12-22 20:39:12 380 [Note] C:/Program Files/MySQL/MySQL Server 5.6/bin\mysqld: ready for connections.

Can you tell me why this occurs and how to restore that data? Is is possible? Do you think MyISAM tables are safer and a switch could solve this kind of errors?

EDIT

More informations about this puzzle.

• This machine has a RAID-1 volume.

• The problem has occourred after a poweroff on 22 december. After this power off I got the previous log and my database had a many-days data rollback. I found the database exactly with data of 14 december.

• From 14 to 21 december there were many graceful server shutdowns (every evening) and I found a full backup for every day from 14 to 21 december. The 22 december backup has the 8days data gap.

I think this is very strange. I can understand data loss after a poweroff, but I can not understand this so big rollback (8days) because during this 8 days there were many server shutdowns and mysqldump backup confirm that all data was correctly stored. I supposed there was a innodb log flush problem, but why so big?

Thanks