Question: Does anyone know if I can install normal 2.5" SATA drives inside an HP DL360 G5 server? Right now it has 6 72GB SAS drives. I am looking for raw storage for my files SAS performance in not required.

Answer: 
I've never had any compatibility issues using SATA disks in HP hardware or with Smart Array controllers. 

A better solution may be to use midline SAS drives if you have the budget. They'll still run at 7200 RPM, but still have a SAS interface (and queuing, etc.). 

I'd recommend the [2.5" Seagate Constellation drives](http://www.seagate.com/www/en-us/products/enterprise-ssd-hdd/constellation/) in either 500GB or 1TB capacities, with a SAS-2 interface. They should be around $200 per disk. The SATA interface versions of the same drives will be about $50 less per disk.

The [HP ProLiant DL360 G5 server](http://h18000.www1.hp.com/products/quickspecs/12476_div/12476_div.html) uses a Smart Array P400i RAID controller in most setups. Performance is helped tremendously if you have a battery-backed write cache unit on the controller. See: [Incredibly low disk performance on HP ProLiant DL385 G7](https://serverfault.com/questions/221541/incredble-low-disk-performance-on-hp-dl385-g7/221553#221553)

Make sure you update the firmware on your internal Smart Array (P400) RAID controller before doing this. See the [HP firmware update page for your model and OS](http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?lang=en&cc=us&prodNameId=3288144&taskId=135&prodTypeId=15351&prodSeriesId=1121486&lang=en&cc=us).
Few times I had a problem with SATA drives inside Proliant servers where under Linux drives were detected as PATA.

The solution was to turn off Auto mode for hdd in BIOS settings...