Dell PERC 5i/R or H200 VMware Performance Fix

I had an old Dell PERC 5i/R RAID card laying around and wanted to use it for a home lab ESXi box (note: also works on Dell PERC H200). The card isn’t amazingly high performance, but it it’s good enough for simple RAID. Well, that is, it’s good enough performance if you change the settings. By default “write caching” is disabled – that unfortunately includes even “write caching” on the drives themselves (5i/R doesn’t have cache so it’s always “Write Through”, the H200 has cache, but is disabled by default). Therefore by default write performance is downright painful.

Fortunately it’s not too difficult to fix if you can pull together the right tools. I was lucky enough to find a post by “tonyd88” on this Dell support forum which explains the process. Below, I attempt to summarize the steps for posterity.

WARNING: If you enable write caching on the 5i/R or H200, because of the lack of battery backup (BBU) there is a risk that if you lose power mid-write, you will corrupt your disk, OS, etc. Not only use at your own risk, but ideally at least have a UPS on your system.

Steps:

  • Locate a copy of “LSIUtil.exe”. The Dell RAID 5i/R was made by LSI. LSI was sold to Avago Technologies and a copy of it appears to be here, but you may need to look around in Avago’s legacy driver downloads. The latest version I have found is 1.62.
  • You’ll need to create a DOS boot disk or thumb drive with the LSIUtil.exe on it. Unfortunately explaining how to do that is a bit beyond the scope of this article. Google is your friend.
  • It is likely you will need “DOS4GW.EXE” also on the boot disk. You’ll have to find a reputable download or buy it here. This may be a potential alternative.
  • Install the Dell 5i/R RAID card in the system and boot to your newly created DOS boot disk/drive.
  • Run the LSIUtil.exe binary.
  • Select your controller. Hopefully there will only be one, but otherwise you’ll have to figure it out. Choose the number that matches and hit <enter>.
  • Select option “21”, “RAID actions” (type 21 and <enter>).
  • Select option “32”, “Change Volume Setting” (type 32 and <enter>). This submenu’s first item is the critical change:
    • On the first prompt for “write caching” type “yes” and <enter>.
    • For “Offline on SMART Data” just hit <enter> for default or change to whatever you want.
    • For “Auto configuration” just hit <enter> for default or change to whatever you want.
    • For “Priority resynch” just hit <enter> for default or change to whatever you want.
    • For “Hot Spare Pools” just hit <enter> for default or change to whatever you want.
  • At the next prompt type 0 <enter> to quit. Just continue to hit <enter> until it drops all the way out to DOS.

You’re done. Pull the boot drive and reboot to whatever OS you’re going to use on it. VMware happily uses the cards.

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