BL 495c with VMware ESX 3.5 (mirroring SSD drives)

[utopiazz]

We are planning to use HP BL 495c blades in a new VMware ESX 3.5 solution.

Since we can't boot from SAN (corporate rules) the option is to boot from internal SSD drives. This works fine in our test solution wich only have a single SSD drive in each server.

In our production environment we want to have the boot drives (SSD disks) mirrored as recomended by HP VMware Solution Sizer.

The problem is that LVM is removed in VMware ESX and because of that we can't mirror the SSD drives.

Is there anyway to get around this and mirror the internal SSD drives in BL 495c?

[Cederberg]

You should be able to use the p700m array controller to make a "hardware" raid which is far better and more stable than a "software" raid..

on server startup you should be able to press "F8" or something to enter raid management when the firmware is loaded for the Array controller. Another way you could try is to use the smartstart CD if thats supported for that array controller..

[utopiazz]

The p700m is not an option in our solution since we are already using the available mezzanine slots for NIC and SAN connectivity.

[utopiazz]

Does enyone know if HP will change the built in dual SATA controller to a built in SATA Raid controller in future releases of this blade?

That would solve this problem.

[Olivier Masse]

I asked the same question to our HP rep when he came to show us these blades, and the answer was that the failure rate of SSD disk is expected to be below that of hard disks so that's why there's no RAID option.

From what I understand, these blades are CPU + memory building blocks for a VMware cluster. If you boot off ESXi from an embedded USB key and put your shared VMFS on your SAN, chances are you will not be using the SSD disks much anyway.

I don't have any bl495c's (yet) so this is only my two cents.

[utopiazz]

I have made a number of calls to both HP and WMware to "solve" this.

The conclusion is that ther is not possible to do what we want. This blade is not realy supposed to boot from the internal SATA controllers. The only time this is to be done is when the operatingsystem isn't supported on USB key or SAN boot.

So for our solution whe have to boot from either SAN or a single SSD disk (we are not going to use VMware 3i).

[Adrian Clint]

I see my earlier message never made it up here. Anyway..

The BL495c only supports software RAID with the SSD disks. Reasons given by HP I have heard are.
1. BL495 target market will be SAN or USB boot. As discussed above.
2. A single SSD is equally if not more reliable than 2x 2.5" SAS in a RAID1 config.

[Phillip Thayer]

The BL495c comes with an embedded SATA controller. This should allow you to build a RAID 1 of the two SSD's to provide redundancy. Although they are solid state drives they still have a possiblity of failure and at a minimum you should have RAID 1 on the drives. To do this you need to go into the controller configuration at boot time and configure them the same way you would configure SATA disks drive. SSD's are seen as SAT drives byt the controller.

Phil

[utopiazz]

@Phillip Thayer

[quote]
To do this you need to go into the controller configuration at boot time and configure them the same way you would configure SATA disks drive. SSD's are seen as SAT drives byt the controller.
[/quote]

I know that from controller point of view there is no difference between SATA and SSD drives. They both use the same interface and both "look and feel" like SATA drives to the controller.

The problem is that the embedded SATA controller can't be configured to run any RAID level at all. There simply isn't anything that you can configure during boot/post. And this is what i think is a major design flaw. HP coukld at least have incorporated the same SATA controller that they use on their desktop/workstations.