Disk Drive Configuration

[mannyeng]

Hello Team.

I have read Users having system configurations having RAID 5 or RAID 1 for ESXi servers. Trying to save money here, I need suggestions on which might be the best option between the three. if you think, you can add suggestions to (1) or (2) or (3) please do so.

Intro: Needs to run 6-7 VMs on ESXi 3.5 with Quad core, 8 GB ram. Its a home/business machine. so trying to cut down costs as much as I can.

1) Have only one disk - 1TB SATA and have a back up to manually back-up VMs weekly using ROBOCOPY.

2) Have two disks 500 GB with other being Mirrored RAID 1. But my concern is whether there will be a delay in working with VMs because of this mirroring.

3) Have no plans for RAID 5, with three disks each 500 GB, but do you see any advantage in having them when using ESXi.

Please share your ideas amongst 1,2,3 and help me pick one. Thanks

Manny.

[Tangata]

Raid-1 is probably your best bet. Raid-0 gives no performance benefits, and no redundancy, forcing more frequent backups. Raid-1 and Raid-5 both provide redundancy. Both Raid-1 and Raid-5 give better performance than Raid-0, and Raid-1 performance is generally higher than Raid-5. However, for an equal amount of storage, Raid-1 is more expensive than Raid-5. However, keep in mind (at least with VMware) that you can easily add a third drive to to your Raid-1 array, converting it to Raid-5, doubling your capacity when/if it your requirements grow.

Lou

[Jackobli]

We are talking about ESXi, right?

You are asking about RAID, so please check the HCL and perhaps also http://www.vm-help.com for RAID controller that are compatible with ESXi. Maybe this will already make your costs to huge.

On any RAID controller, RAID1 don't will make your disks slower (ESXi -> Controller buffer -> two parallel write requests).

On RAID5, it depends on the CPU of the controller.

But having lots of guests writing to a single disk may limit the performance quite badly. Depends on what your guests are doing.

Beside RAM, disk i/o is the most common source of low performing guests.

[mannyeng]

Thanks Lou.

[mcowger]

I disagree with Jackobil here.

RAID0 ALWAYS has better before than RAID5 for the same number of disks. It also has a MUCH high risk profile, and you shouldn't use it for anythingyou care about. Unless you are running high IO VMs, I'd go RAID5 with 3 disks. If you cant afford that do RAID1.

--Matt

[Tangata]

Raid-5 is cheaper per unit of storage, but in a real-world scenario, Raid-1 probably is the better choice. It is a subtle analysis that does not lend itself to a simple ROI calculation. Let’s assume a 500GB drive costs $100, and a 1TB drive costs $125. (This is about what the drives cost in the USA.)

1) With two 500GB drives in a Raid-1, you have 500GB of storage at $0.40/GB and a total cost of $200.

2) With three 500GB drives in a Raid-5, you get 1TB of storage at $0.30/GB, and a total cost of $300.

3) However, with two 1TB drives in a Raid-1, you get 1TB of storage at $0.25/GB, and a total cost of $250.

If you are never going to need more than 500GB, then choice #1 is the cheapest. However, if you think you will need more than that within a year or two, then in my opinion #3 is clearly the best choice.

Lou

[Jackobli]

RAID0 ALWAYS has better before than RAID5 for the same number of disks.

Did I wrote anything about RAID0?

Matt, really, anybody using ESXi for running servers will never even think about RAID0!

>I'd go RAID5 with 3 disks. If you cant afford that do RAID1.

RAID5 with 3 disks on what kind of RAID controller?

The OP wrote about "costs". Tell me any HCL compatible RAID controller that is cheap (and does very good performance).

[mannyeng]

My next step will be to research HCL and see if Jacobli's information regarding cost is true.

I was told about a whitebox website and in "Complete system" Forum, the costs of such a configuration with RAID 1 was within $600. May be I am wrong, but I need to research. Will get back to you.

Anyways, Jacobli, what do you think, might be a configuration you recommend and the cost that might add up to? when you say costly, what is your range? this will clear some questions.

Thx.

[Jackobli]

Perhaps you explain what kind of guests you will run on your ESXi host. What disk i/o do you expect.

If you are on low budget, you will go and use SATA instead of SAS drives So you need a controller that does support SATA. Have a look into the IO-Guide pdf, pages 16 and following.

I would go with RAID 1 for system and RAID5 or RAID6 for low io guests, RAID 10 for high io guests. And I would NOT go with just 3 drives into RAID5. I my business would depend on that host, I would also go with one or more hot spares.

Do some research for your backup. Free ESXi has some flaws for backup.

[Jackobli]

Dang, again, wrong thread...