Non local storage options

Hi Boom:
Hosting repositories on CIFS is generally speaking a bad idea and should be used only temporarily, in specific situations. Besides being slow, CIFS is not reliable for large transfers.
This is due to the fact CIFS is not designed to deal with large amounts of data and all optimizations have been performed based on this assumption. Moreover, backing up is not equivalent with copying. The speeds you see are the ones supported by CIFS with 8KB blocks transfers without caching (the cache fills up fast and stays filled until data is committed to storage).
The high speeds you see are most likely reported based on caching the transferred data in the memory (from where it is committed to storage in its own time).
The best indicator of the speeds to be expected is the IOPS available on the repository storage although multiple other factors are to be considered.
Data transfer is slower over NAS than using DAS or a SAN. RapidRecovery conducts multiple operations on a variety of levels, requiring many simultaneous or overlapping reads and writes. A typical example includes three agents backing up simultaneously, perhaps with replication, and on any given day may include virtual standby, nightly maintenance, SQL checks, Exchange checks, and so on. These all have read or write operations that have a more significant impact on network performance than a repository using DAS or a Storage Area Network (SAN). As such, putting the repository on a NAS places a substantial load on the NAS, with the network acting as a bottleneck for the many required read and write operations. Total throughput is lower than can be achieved using DAS or SAN. As such, a better solution that you may have available at your location is iSCSI as most storage devices (including Windows Storage Server) support it.
Hope that this helps...

So, the short answers to your questions:

- Is it a normal behaviour with CIFS storage with Rapid recovery to get such slow speeds?

YES

- Is there other way to save files to non local , like FTP? 

YES -- iSCSI

- How can i get good write speed on external storage.

USE iSCSI on storage that supports reasonable IOPS