RAID on my HP ML115 G5 ESXi server

Continuing with my exploits at rebuilding my HP ML115 G5 based home server running ESXi 5 I’ve now turned my attention to data resilience by looking at a hardware RAID solution.

After a bit of research I decided on using an HP Smart Array P400 Controller as it seems to be a good balance between performance and cost, particularly when coupled with the optional 512MB battery backed accelerator cache. Another reason for choosing the P400 controller is that it appears on the VMWare ESXi Hardware Compatibilty List.

There are lots on eBay for a reasonable price, many of which appear to be pulled from decommissioned enterprise rack servers. I got mine for £60 including the 512MB cache and battery.

The P400 features 8 channels split across two SFF8484 connectors. Typically these are connected to hot swap SAS drive cages but they can also be connected directly to attached SATA drives using an SFF8484 to SATA breakout cable, such as this one sold by Startech.

I’ve never used a hardware RAID solution before so it’s a new learning experience for me. The process involves using the HP Array Configuration Utility (ACU) – which can be booted from CD/DVD or USB flash drive – to create a new array containing the desired physical drives, and then on this array creating a logical drive in the required RAID scheme. For my initial tests I’m going to use a couple of HP 160GB SATA drives configured as a simple RAID 1 mirror which will hopefully give me the data resilience I need. With more drives available other options such as RAID 1+0 or RAID 5 are possible.

I want to do some testing with this configuration, including ensuring it works fine with ESXi and also by removing one of the drives to simulate a failure so I can understand how it handles an array in a degraded state and how it recovers. Assuming everything goes well and I am happy with it all I will then look at converting my current live ESXi installation over to RAID 1 scheme using the existing 250GB HP SATA drives I have. Fingers crossed it all goes OK!

The dead HP ML115 – the plot thickens…

So, I’ve now replaced my dead HP ML115 G5 server with one bought on eBay and built a second one from a combination of parts from my original broken one and another bought for a bargain price on eBay.

Once the second ML115 G5 was built, I just thought I’d try the old “broken” motherboard in this new chassis… and lo and behold, it works!

When I previously investigated the problems with my original server, there was no sign of life when powered up. No motherboard LEDs lit, no fans and no response to the on/off switch. So I tested the HP power supply out of the chassis with a couple of hard drives connected and shorting the connectors for the on/off switch. The PSU fan and hard drives span up suggesting the PSU was OK. I then tried an old, spare non-HP ATX PSU I had lying around and this didn’t seem to work either. So my conclusion was that either the motherboard or the chassis wiring was at fault – with the motherboard being my strong suspicion.

Well now I know that the motherboard is OK. The original motherboard works fine in the original chassis with one of the “new” PSUs. I’ve also just tried again with the spare non-HP ATX PSU and it works! So my investigation and testing of the PSU was woefully inadequate.

I suspect that genuine replacement HP PSUs are going to be prohibitively expensive so I’ll either look for a used one on eBay or look at using a non-HP ATX power supply instead (the only downside of the latter being that the HP PSU is a non-standard size – it’s smaller – and so fitting a standard ATX PSU in the chassis needs some minor modifications for additional mounting holes and also leaves a gap between the PSU and the top of the case).

I’m going to have enough HP ML115 G5 servers before I’m done to start my own mini datacentre!