There is no "best raid level". Depending on your requirements you have to make decission between "capacity", "performance" and "safety".  You will only get one of the three. If you want to get two you always have to spend some more money because extra disks are needed to archive your goal. There are some variables like large and slow harddrives (think about a 10TB disk) and rebuild times in a case of a drive failure within a raid. Depending on how long it takes it increase the risk of a double drive failure. A double drive failure can be survived with a RAID6 or if youre a lucky one with a RAID10 (if Mr. Murphy is nice to you). The table i mentioned in the first post is shown here [URL] But just grab the manual of your PERC6. With only 2 disks go for a RAID1. The 2x300 gives you a capacity of around 285GB and depending of the OS and choosen filesystem you have ~275 at the end. I suggest to replace the PERC6 battery before getting the server back into "production" and please backup your data on a regular basis. The initial configuration of the PERC6 within these old servers is quite simple and i like the DOS like menu very well because i was familiar with it(we are a dell shop). But you should also install OMSA as an application later to get some insights from the OS level too. OMSA comes also with command line tools like omconfig and omreport. I cant remember if special megacli tools also works with old PERC6. Good luck.  
Hello, i will will transfer my website from hosting company, to server which i bough and will hosted it by myself. DELL Poweredge R610 2x300GB SAS Drives  2xE5620
Dell Poweredge R610 RAID