Hot Swap drive with different hard drive brand and size

All drives in a 2950 will be hot-swappable.  The brand and size don't matter as long as it is a Dell-certified (co-branded) drive and it is at LEAST as large as the drive it is replacing.

Thanks PowerEdgeTech, but how can I tell (what are the signs) when the drive in RAID 1 or RAID 5 goes bad?

Since Dell doesn't sell 2TB drives for the 2950, I might assume that the drives are either generic/retail drives or that they are normally sold for other Dell systems (R710, for example), in which case it might technically be tuned for the same controller - PERC 6 (the PERC H-series as well).  If retail, and you are having problems, it may be for reasons dlethe has described in detail (non-certified drives), rather than some physical problem with the disk(s).

Don't know how fussy Dell are but HP controllers won't let you replace a SAS disk with a SATA one or vice versa.

Same on the Dell's ... SAS and SATA can be mixed on the same controller (like he has - SAS for OS and SATA for data), but not on the same array.  So for his setup, drives in the RAID 1 must be replaced with SAS drives and drives in the RAID 5 must be replaced with SATA drives (2TB near-line SAS drives exist but won't work as replacements - which is probably not a problem anyway given their price).

My 2950 has Perc 5 (NOT Perc 6). I don't if that makes any difference.
I bought 4 of the 2TB from Adventis, they said that they're for 2950 (Hot Swap).
I don't have problem yet, but want to get another one (cheaper) to have it on the shelf ready, in case one of 4 drives goes bad.
and want to do the same thing for the 73GB SAS in RAID 1.

I can tell you if they're Dell drives or not ... if you want to know ... in OMSA (if you have it installed), go to Storage, PERC, Backplane/Enclosure, Physical Disks and tell me the firmware revision for the drives.

I can't go to Storage, PERC, Backplane/Enclosure, Physical Disks"
but I was able to print screen of the OMSA (attached).
Thanks

Dell-Online-Diagnostic.png

That screenshot is from the Online Diagnostics, not OMSA ... it has the info in it though.

The model HDS72302 is a Desktop/Consumer Class drive (HDS stands for Hitachi DeskStar), which is worse than having non-certified generic Enterprise-class drives - might be worth a call to Adventis to question them on it:
http://www.hitachigst.com/internal-drives/desktop/deskstar/deskstar-7k3000

The

OK, thanks.

I can't find the link to download the OMSA (OpenManage Server Administrator - the management software that interacts with the server hardware)? Do you have the link? or do I have to purchase it?

No, it's free (listed as Server Administrator Managed Node in download page):
ftp://ftp.dell.com/sysman/OM-SrvAdmin-Dell-Web-WIN-6.4.0-1266_A00.18.exe

Download and run to extract, then run C:\Openmanage\windows\setup.exe.  Choose Custom and make sure Storage Management is installed.

Thanks guys.