markshrimpton
Contributor
Contributor

Hard Drive RAID configuration for R610

Jump to solution

Hi All,

I am new to virtualisation, and having read many, many, documents i think i am starting to get my head around the various concepts in the installation and running of ESXi and VMs.

My plans are to purchase a Dell R610 with the 'ESXi v4.0 2CPU Embedded, Basic 0yr Upgrade Subscription, on SD card' which I think gives me the basic ESXi host which can be remotely managed using VMWares free Vsphere Client?

I am unsure however of the best way to configure the machine's hard drives.

Originally I was planning RAID1 on 2x 15k 146GB and RAID5 (1 HS) on 4x 10k 146GB with the RAID1 for the VM's system drives and the RAID5 for their data etc.

But i think i may be missing something fundemental about how VMs are different to normal physical machines? Is it easy/possible/worthwhile to have a VMs data on a seperate hard drive to it's OS? None of the planned VMs are very taxing on hardware.

Is it better say just to have RAID5 (1 HS) 5x 146GB or RAID10 6x 146GB, would 15k vs. 10k make much of a difference?

Currently all VMs and their data will be stored locally. Should the delve into virtualisation be successul then will look into DAS or more likely a iSCSI SAN in the future.

My apologies that this is largely about the possible hardware rather than all about ESXi. I hope you may be able to give some advice though.

0 Kudos
1 Solution

Accepted Solutions
J1mbo
Virtuoso
Virtuoso

Broadly agreeing with Sixth, what is needed is a storage subsystem capable of delivering the number of random IOPS consistently as required by the many running VMs.

The PERC 6i in these machines is a fast controller - hence one RAID-5 volume with as many high speed disks as possible will give the best overall performance. Don't bother seperating out the VM system drives, this was never really of benefit anyway, and wastes IOPS as there are then less spindles available to service the overall concurrent workload.

Be sure to spec the BBWC (think it is standard on that server anyway).

Also as an aside I noticed that the cost is nearly halved with 48GB RAM as apposed to 64GB.

Please award points to any useful answer.

View solution in original post

0 Kudos
4 Replies
s1xth
VMware Employee
VMware Employee

My Opinion.. see indents:

I am unsure however of the best way to configure the machine's hard drives. Yes this is correct. All you will need is ESXi on an SD card. Technically speaking, you could just order the SD card installed in the server and install FREE ESXi if you feel you are not going to use the features of ESXi Standard etc.

Originally I was planning RAID1 on 2x 15k 146GB and RAID5 (1 HS) on 4x

10k 146GB with the RAID1 for the VM's system drives and the RAID5 for

their data etc. My opinion....do one big Raid 5 or one Raid 10.

Is it better say just to have RAID5 (1 HS) 5x 146GB or RAID10 6x 146GB, would 15k vs. 10k make much of a difference? Well this depends on your data, SQL? Exchange? 15k drives. If you are running file shares, anything with low to medium i/o then 10k is fine. Raid 5 or 10? Depends on how much space you need, if you NEED space on the server, use Raid 5. If you want the best performance but loosing space is not a matter to you, then go Raid 10.

http://www.virtualizationimpact.com http://www.handsonvirtualization.com Twitter: @jfranconi
J1mbo
Virtuoso
Virtuoso

Broadly agreeing with Sixth, what is needed is a storage subsystem capable of delivering the number of random IOPS consistently as required by the many running VMs.

The PERC 6i in these machines is a fast controller - hence one RAID-5 volume with as many high speed disks as possible will give the best overall performance. Don't bother seperating out the VM system drives, this was never really of benefit anyway, and wastes IOPS as there are then less spindles available to service the overall concurrent workload.

Be sure to spec the BBWC (think it is standard on that server anyway).

Also as an aside I noticed that the cost is nearly halved with 48GB RAM as apposed to 64GB.

Please award points to any useful answer.

0 Kudos
LucasAlbers
Expert
Expert

good points.

The dell rep pointed out that this is triple channel memory, so you want your memory in multiples of 3.

We pick raid 10 for better write performance and a better chance of handling more than one drive failure, assuming the 2nd drive failure is not in the same set.

We argue over whether raid 5 + 1 spare or Raid 6 is a better option after raid 10, if reliability is the most important consideration.

Raid 5 + 1 spare does not have the write hit that raid 5 does...would raid 5 +1 spare == raid 6 for write performance?

Make sure you enable writeback cache and install openmanager.

Openmanage will do background raid consistency checks, and predictive drive failure.

J1mbo
Virtuoso
Virtuoso

> Raid 5 + 1 spare does not have the write hit that raid 5 does...would raid 5 +1 spare == raid 6 for write performance?

A hot-spare does nothing unless there is a failed physical disk, hence there is no overhead to performance. The point about the PERC 6 controller is that it is fast - it's write performance with RAID-5 will likely exceed that of the 5 physical disks and so not be a bottleneck.

Please award points to any useful answer.

0 Kudos