U2 Storage system and Backup

[Jon Fayers]

I have a U2 Storage System which had 3 x 18.2 Gb drives in it. The Array was configured as RAID5 I need some additional storage as it was almost full so I put another 18.2Gb in the Spare slot and added it as an additional logical drive to the same RAID 5 set. Now I decided to move some data from the orignal logical drive to the new logical drive and the best way to do this was to back it up ( using Data Protector) and recover it to the new logical drive. The speed of the Backup was incredibly slow 4MB/second at the most.... I had noticed this before on other U2 Storage systems that I have but thought that it was a limitation of the product itself .... until I restored the data to the new logical drive. Backup of 2.85Gb took 3 hours whereas the restore took 30 mins.
OK so I thoughht that was a bit strange so (although I couldn't see)why decied to backup the new logical drive .... same result 3 hours to back it up......Any odeas why it should be sooo slow to backup and yet much much quicker to recover?

[JohnWRuffo]

Jon:

What is the value setting for the cache on the Array Controller?

50% read and write?

or 100% write?