An HP 5i is a original parallel scsi controller, non SAS. That is an old controller, indicating to me that your server is a few years old. If your DL380 has that in it, then you probably need 3.5 inch scsi drives. A DL380 should have 4(?) bays in the front. To mount drives in the open bays, they will need to be in the Compaq/HP drive trays. At one time, installing non Compaq/HP drives on their array could burn the raid card out. If you have two drives and they are on the raid controller, then they are probably in a mirrored configuration. If you hope to add drive space to the existing array, you would probably need to add two drives and convert the raid 1 to a raid 10. Windows will not automatically see the new space. If you then want to capture the new available space you will need partitioning software to access the new empty space. Acronis has a server capable product for this. There is a command line utility to change Windows partition sizes, but it is not for the faint of heart. I do not think you can add a single drive to a mirror and convert it to a raid 5.
The safer way would be to add two more drives, put them into their own mirror and then move some data from the original drives to the new ones. If this data is in a network share, a new share would need to be created, then everyone would need to have the location remapped, or their logon script edited to reflect the new location.
None of the above mentioned stuff is anything to be taken lightly. If you are not familiar with arrays in servers and how to configure them, I'd suggest finding a company in your area that works on HP servers. While it may not be hard to do, it helps to know what you are doing so you don't crash the server.
This place sells all sorts of HP stuff, older items included, and you should be able to contact them and get the right drives for your server.
Sillworks
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