Non-RAID SSDs or SAN Boot for Enterprise vSphere Deployment?

[M_Hughes]

Hi guys,

I have a customer who has purchased HP BL460c G6 blades with dual 32GB SSDs but no RAID controller, and no capability to add one as both mezzanine slots are in use (for NICs and HBAs).

This is obviously sub-optimal - the configuration was recommended by HP and procured prior to the client engaging our services for analysis and design.

I am trying to assess whether it is preferable to install ESX to the non-RAIDed SSDs, or to instead SAN-boot the ESX servers.

While I would never recommend installation of a production environment to non-RAIDed mechanical drives, I am inclined to believe that the superior reliability of SSDs mitigates much of this risk. However, SSDs in the enterprise as too knew to be a known quantity in terms of reliability.

At the same time, I am aware of the complexity of a SAN-booted solution, the lack of path redundancy until late in the boot process and the potential for SAN fabric issues to take out all ESX hosts.

Does anyone have any experience with a similar situation, or is able to provide general recommendations or advice?

In addition, I am having difficulty locating detailed configuration recommendations and design constraints for a SAN-booted ESX 4 environment. I am aware that historically SAN-booted ESX hosts lacked support for a number of features (RDMs in 2.x, MSCS in 3.x, etc) and that there have previously been design constraints around, for example, LUN numbering for boot LUNs. However I cannot find this level of detail for ESX 4 - again, if anyone can provide this informatio, best practice recommendations for ESX 4 SAN boot LUN configuration, etc, I would be much obliged.

Thanks in advance!

[AndreTheGiant]

SAN boot seems the most "professional" and "enterprise" solution.

But as you say there is a more complexity.

For more info you can see from page 43 of:

http://www.vmware.com/pdf/vsphere4/r40/vsp_40_san_cfg.pdf

The "embedded" solution seems the future... small, simple, cheap.

For few hosts I think that this could be the best solution.

But you need to plan a solution to backup your SD/Flash/USB to a similar device (maybe a simple USB keys)

Another idea is use a provision solution (like Altiris) to "deploy" the host image.

Andre

[M_Hughes]

Thanks for the feedback. I am curious to know if anyone has configured ESX on non-RAID SSDs for a production environment or has general experience of SSD reliability in general.

Cheers

[AndreTheGiant]

See also this thread:

[TimPhillips]

For implementing SAN boot I would also recommend you to read technical paper Configuring StarWind with a host bus adapter for iSCSI boot.Cause you`re not using Starwind (while it`s not bad s/w target), you can use thisTP as a guidance.

[dconvery]

If you buy a blade with ESXi "pre-installed", You get it on a USB stick that you insert into a port internally. This is a single point of failure, just like an SSD. The MTBF for SSDs and USB sticks is pretty decent compared to SAS disks because there are no moving parts. The idea is that if an SSD fails, HA will take over and everything will come back up. In theory, you can use SIM to recognize a pre-failure alert and put it into mainenance mode.

If you are concerned with the SPOF, then SAN boot is the way to go.

Dave Convery

VMware vExpert 2009

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