On Thu, Jul 15, 2010 at 4:19 PM, Florian Lengyel <[email protected]> wrote: > We're attempting to get the specifications for the holding disk of an AMANDA > server with 6GB SAS controllers that will be connected to an LTO5 drive. > > We want to know whether 7200 RPM SATA drives would be sufficiently fast > for the holding disk (this will be a separate RAID unit), or do we need faster > SAS drives to prevent shoe-shining?
You should probably look at the raw *observed* throughput of your SATA drives and of your tape drive, and then apply a healthy margin of error. That margin accounts for any interference (e.g., interrupt queueing) between the two subsystems, as well as filesystem overhead on the SATA drives. This, of course, assumes that you have enough CPU to move that much data. No, it's not particularly predictable - such is life with a portable backup application! If Amanda was a hardware appliance, the numbers would be much more predictable. Others may have some experience that they can share to help you out - although with no replies in 3 days, maybe not.. Dustin -- Open Source Storage Engineer http://www.zmanda.com
