RAID configuration on HP Proliant DL360 G7 server?

[LazyD]

Hello,

I am planning the hard drive installation for a server rebuild. I plan to use raid 5 on as many volumes as possible but since the server only has 8 2.5" SAS drive bays, there is only the possibility for 2 RAID 5 setups and then space for an additional raid 0 or 1.

I will be installing server 2008 64 with Hyper-V as a host for 2 other virtual machine installs of server 2008 64 (so 3 server os installations in total).

I want to install 2008 on one raid 5 volume (that's 3 of my bays gone) and then I want to create 2 more raid 5 volumes, one for each of my virtual machines. I will be installing the virtual hard disk files of the virtual machines each on their own volume, each volume created from one of the raid 5 setups. This way they will have their own dedicated raid 5 array which hopefully will give good performance while having a bit of fault tolerance.

So my problem is that I don't have enough bays for my plan. I do not have any experience of using seperate rack mounted nas drives with raid controllers. Can I add an enclosure to the rack that can take at least 3 more drives (would be desirable to add expandability for 6 more drives as I need to add a further general network storage volume later)? What are my options in connecting this with the G7 server? Will it use a SAS (scsi) bus from the server or should it be seperate with it's own raid controller and be accessed through the network? Which will have better performance, linking the new raid enclosure to the existing server or having it as a stand alone nas solution accessed though its own network interface?

Also, since the 2.5" sas drives are expensive, would be good to get something that can take the cheaper 3.5" (as long as they are 10k rpm), I'm saying this assuming that the only disadvantage of the 3.5" 10k sas drives is the size?

Can the raid controller in the HP DL360 G7 (P410i) even support 3 raid setups?

Would be brilliant to get answers to my millions of questions.

Thanks!

[djaburg]

My first question would be what are the servers being used for? Most file servers or email servers could easily provide excellent performance on a single RAID5 array, eliminating the need for to many arrays. While disk access can affect performance in a VM, processor speed and number of cores, along with amount of RAM will have more of an impact. That model being a 1U chassis, I'd be concerned with having every drive bay full and the amount of heat being generated by the drives, hopefully there's adequate cooling where the server will be.

[LazyD]

Thanks for your reply.

My original plan was for 3 raid 5 arrays, host on first array, first vm on second array, second vm on third array. But since I would need 9 hard drive bays for that, and I only have 8 in the server and adding bays would be expensive, I have revised it a bit now.

This is what I'm now considering:
2 drives in raid 1 for host os (this machine would only be used for hosting the virtual machines)
2 drives in raid 1 for vhd1 (this vm will be used to host one DB server, only about 10-15% max of network clients would ever access this)
4 drives in raid 1 + 0 for vhd2 (this will run the bulk of the network, will be a dc and serve all users shares)

I'm thinking that I can go ahead straight away with this setup after buying a couple of drives. This would greatly reduce the cost (wouldn't have to buy more raid controllers and enclosures) and I'm not sure how much of a performance benefit we will get from all arrays being in raid 5 rather than two raid 1's and one raid 1+0? This way everything still has redundancy and the bulk of the work can be done by the raid 1+0 setup. What do we think about this?

Thanks.

[Wand3r3r]

You should always plan on hot spares [allocated drive(s) for auto drive failover].

BTW we usually refer to raid 1+0 as raid 10 so its not confused with raid 0+1.
Raid 10 is a stripe of mirrors which can experience a single drive failure in each mirror [2 drvs] before being compromised.
Raid 0+1 if you lose one drive you are a stripe set which has no fault tolerance.

LazyD you are concentrating on the disks but if running virtuals its memory and cpus that are more important. You want a min of quad processors and more then 8gigs of memory.

I would also suggest multiple nics which would be dedicated to each host/vm

[LazyD]

Server has 4 nics, enough for each vm. Server has 2 six core processors and 12GB of ram, soon to be 24GB. Are you saying you think there should be 4 physical processors? That's not gonna happen, only 2 slots.

In regards to the raid setup I am proposing, what do you think Wand3r3r? I also understand that it's the max amount of disks which isn't going to do the temperatures any favours but the room is very well cooled.

[Wand3r3r]

quad core is 4 processors on one die. You have 6 so you are just fine. Server specs are great so no issues there.

Well cooled room and good ventilation you should be fine.