Please suggest a server

A budget and what oracle apps you plan on testing would help?? I'm assuming you're in the states, but country would help if otherwise.

Any preferences regarding manufacturer and would you be alright with DIY??

How many cores does each VM need or as a total to share?? Any Network requirements?

As you're asking for a "server" and not a "workstation" i assume you need IPMI and all those assorted features?

What kind of storage needs do you need as well? Is it Rack or Pedestal mounted?? Redundant PSU's? How many RU's?

If your applications can scale out, or you need more VM's later on it's possible you could go a 4P amd server, but if you need single thread performance Intel is obviously the way to go.

For a off the shelf computer i'd either get an HP or an IBM, and for DIY i'd probably end up with a supermicro board. All my choices for this gig would be a 2P E5-2600 series (or IVB-E when that comes out, not sure on the release date) server with 64gb of RAM. If your requirements aren't so high, and each VM only needs 1-2 threads you could probably get away with a 1P server e5-1600 on a board with IPMI etc.

Since this is more of a DIY forum i'll tell you i'd spec for this job (if you give me a budget i'll get links on the best deals i can find etc):
2* E5-2620 - ~$845 (if you need more ghz there's faster models) (2ghz 6C/12T SNB-E)
Supermicro MBD-X9DRL-iF-O - ~$360

32gb ECC ram- $130-260 (depending on density, speed etc)
64gb ECC rdimms - $320+ (density+ speed etc)
What i picked - 4*16gb (64 gb) dimms - ~$510 (2 channel may be enough for your application, you only have 8 slots, so you can upgrade later)

Total for this - ~$1700

I'd need enclosure + power + storage requirements if i can help you with the rest, or find you a built to order server from HP or IBM (or other if you need a certain manufacturer).

An IVB or Haswell 1P server with a xeon E3-1200 series with a C series chipset is also a good idea if the budget is less and you require ECC RAM, IPMI or other features and don't want a Q series chipset.

If this is more of a "workstation" and you don't require any actual "server" features, the cheapest haswell board with 32gb of RAM, an i7 and a dual/quad port intel NIC for ESXI may be a good idea. This

1155 boards such as the X9SCA-F or 1150 boards such as X10SLL-F are both suited for E3-1200 servers. GhislainG is right about the 82574LM needing drivers though, so with the IVB boards you may want to watch out for NIC drivers yes, i'm unsure about the i210AH and i217 on the X10 boards though.

I'm unsure about availability in India, this may make purchasing custom hardware difficult. Ebay may be your best bet, although i don't know how much postage will cost?? In terms of off the shelf hardware, i love server grade stuff and IPMI when i'm out, but for this any desktop will do with lots of RAM. If you only like spending on hardware once, getting a 2P motherboard and one CPU, so you can expand later if your requirements change might be nice. E5 series xeons can handle Rdimms so you can pack a lot more RAM (not limited to 8gb dimms, you can get 16gb, 32gb as well) as well as having more than 4 RAM slots per CPU. DIY saves you money so if you're up for learning how to put a computer together you can get a faster system, or one more upgradable.

The other option is to have a look at HP or IBM's site and looking at their servers. I'm also assuming you need a tower server as this will be standalone?? Assuming HP has their prices similar in india, or they'll ship it their cheap enough, the "ML310e Gen8 v2 Server" ($1300) with the E3-1240 V3 may be a good deal, it comes with 8GB of RAM (1 UDIMM), which you can then upgrade at ~$30-50 a stick to 32gb (if that doesn't void the warranty?) they change quite a bit for memory ($140 a stick for HP ram kits), i'd also purchase the iLO (IPMI) addon kit as well, it's only $50 but can save you if you want access when you're out (at school/work for instance?). I wouldn't get the 1220 as it doesn't have hyperthreading (which doubles your threads - good for VM's).

In IBM land, there's a few x series servers you could look at. The x3100 M4 (it's IVB though, so it's like the ML310 gen 8 but not v2) is similar to the ML310e, except its noise profile is much higher. If you're going to have this at home, many servers are quite loud FYI, you might want to lean towards the ML310e which in the data sheets is quieter.

All in all, you might be able to talk to an IBM or HP dealer near you and pick up a clearance IVB model instead of a haswell model. Make sure you get at least a 1230 though, otherwise no hyperthreading. Check the NIC's as well if you're going ESXI.

Personally i dislike virtualbox, i'm a QEMU-KVM guy, but virtualbox is oracle so getting that experience may be better, if OEL is just going to be the hypervisor and that's all, ESXI i think will need less hardware.

Personally i'd do these options in price order-
-get a desktop and not worry about a "server", DIY with the cheapest i7 haswell (they're price parity so who buys old technology unless you can find an excellent deal)(unless you want to overclock or need GPU don't get a K series)

-buy a prebuilt desktop with 4 ram slots (so 32gb of RAM) and an i7 for the best price you can

-DIY a 1P E3 series haswell server

-get an ML310e V2 with the 1240 V3 and upgrade the RAM.

-DIY and get a 2P motherboard with lots of RAM s lots but only get 1 CPU for now.

DIY and get a 2P server with everything

Buy a 2P ML310e and upgrade the ram yourself.

If your budget is ~$1200 i'd do a 1P DIY xeon E3 build, if it was more like $1500-1600 i'd do the 2P mobo with 1 CPU for now, if it's 2k+ i'd DIY a 2P server (although that's really overkill for learning).

If you'd rather spend the money on something else a DIY haswell desktop could be had for ~$800, an i7, 32gb RAM, ATX motherboard, Platinum PSU, 2tb HDD and full tower case (just in case you need 10 HDDs etc). You'd then have to purchase a network card or two for ~$100, but for testing/education internal networking i think will be fine?

which reminds me, if you're going to be running this alot and pay for your own electricity, at my place running that ~$800 i7 i said above would cost ~$490 a year with the platinum PSU if i ran it 24/7 (24.5 cents per kilowatt hour) versus with a 80+ bronze it would cost ~535 a year, whilst the PSU only costs ~$80 more, which means i have a payback of less than two years, so keep that in mind before you get an off the shelf HP with a less efficient PSU. If electricity is cheap or you can leave this at work and power on with IPMI, you don't have to really care.

Cheers,
BBCXC.

To be more specific (the CPU and motherboard are in my list), I used two kits of CORSAIR Vengeance LP 16GB CML16GX3M2A16600C10 mainly because someone else used the same memory kits and they worked fine. The PSU is an Antec High Current Gamer Series that I had laying around and it's more than I needed for such a system. The hard disks are WD Caviar Blacks and a Seagate Barracuda 7200.14 ST3000DM001. The case isn't important; it should be large enough and provide good cooling. I use the stock Intel fan which is fine for a server. Overall I'm happy because the system is fast enough and quiet.

I selected the mobo because other builders successfully used it with ESXi and Windows Server 2012. You could start with the Q87 equivalent and a Haswell non-K CPU, but the new LAN controller may not be supported in ESXi. Unless you find someone who has tested teh same configuration, you're on your own.

I presume that you already know that only expensive server motherboards include a RAID controller (usually LSI) compatible with ESXi. That wassn't an issue for me as I could live with individual hard disks and I didn't want to spend over $500 on a motherboard plus another several hundreds for ECC memory.