Thursday, April 18, 2013

Striping the boot volume across 2 SSDs for non-storage experts

If 1 SSD is good then surely 2 must be better? Smile

For a variety of reasons, one of which is to minimize compile/build times, I decided to try striping (RAID-0) the boot volume across 2 SSDs. My dev box is an HP Z420.

I’m a PC hobbyist not a storage expert. The answers to these questions might be obvious to someone more conversant with storage parlance. Posting this with hopes of helping other PC hobbyists enjoy maximum performance with minimum frustration.

Comments/fixes/errata welcome.

Can I get away with not using RAID at all?

The idea here was to use Windows 7 Dynamic Disks. This is very easy to setup and requires no extra hardware. Unfortunately Windows can’t boot from a dynamic disk.

Ok, How about Intel RAID since it’s built into the motherboard?

This *will* work but presents another problem. I’m striping SSDs. SSDs need TRIM support to extend their lifespan. Intel added TRIM support for it’s RAID solution (called Rapid Storage Technology) but only for series 7 chipsets. The HP Z420 ships with a C600 chipset which I presume is series 6. So no luck.

What’s this LSI RAID stuff in the “BIOS”

The firmware config (aka “BIOS”) has support for optional add-in RAID cards. One of which is the LSI 9212-4i. Apparently this falls somewhere between a standalone RAID controller add-in card and software RAID. And it’s relatively cheap – about $130

WTF is the LSI 9212-4i HBA?

While tracking this down I encounter an unfamiliar acronym (initialism really but no one uses that word properly). HBA is short for Host Bus Adapter. It’s a way of splitting the RAID implementation across the motherboard and an add-in module without requiring a full standalone RAID controller add-in.

Great, Does it support TRIM?

According to the LSI website TRIM is supported for LSI HBAs using an IT firmware (as opposed to an IR firmware). 2 new unfamiliar acronyms:

  • IT – Initiator Target
  • IR – Integrated RAID

I have no idea what these mean – that’s a Wikipedia surf session for another time. Turns out that the LSI 9212-4i HBA supports BOTH!

Both? At the same time? How quantum mechanically confusing!

Does it support both at the same time? Or is it in one mode or the other? Does it support both for UEFI and traditional BIOS?

Apparently it ships with IR firmware (usually) but that can be overwritten with IT firmware by following these instructions.

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