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rants, tips

Hassles with Intel RAID – Rapid Storage Technology

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I have recently fitted a new Intel DH67CL motherboard and decided to use the on-board RAID controller to achieve resiliency against drive failure. I have four 1TB Sata drives, and chose to create two separate mirrors. This is not the most efficient form of RAID, but mirroring is the simplest and easiest for recovery, since if one drive fails you still have a complete copy ready to go on its mirror.

I thought this would be a smooth operation, especially since I have two pairs of identical drives. Everything was fine at first, but then I started to get system freezes. “Freeze” is not quite the right word; it was more an extreme slowdown. The mouse still moved but the Windows 7 64-bit GUI was unresponsive. I discovered that it was possible eventually to get a clean though time-consuming shutdown by summoning a command prompt and waiting patiently for it to appear, then typing shutdown /s. After reboot, everything was fine until next time, where next time was typically only a few hours.

I was suspicious of the RAM at first and removed 8GB of my 16GB. Then I discovered that others had reported problems with Intel RAID (also known as RST) when you have two separate arrays enabled. The symptoms sounded similar to mine:

When the second RAID array is enabled (tried both RAID1 and 0), Windows (Win 7 Ultimate 64bit) will freeze after 10+ minutes of use. This initially manifests itself as my internet “going out”. While I can open new tabs in the browser, I cannot connect. I can’t ping via CMD either. I can’t open Task Manager, but I can open Event Viewer (and nothing really is shown in there re: this). If I try to Log Off or Restart the PC via Start Menu, Windows hangs on the “Logging Off” or “Shutting Down” screen for at least 10 minutes, up to several hours (or indefinitely).

There is no solution given in the thread other than to remove one of the arrays.

The system is 100% stable when I remove the second RAID1.

says one user.

I broke both of the mirrors and used the system for a while; everything was fine. I found an updated driver on Intel’s site (version 10.8.0.1003, dated 17th October 2011) and decided to re-try the RAID. Now I had another problem though. Note that I was using the Windows management utility, not the embedded utility which you get to by pressing a special key during boot, since it is only with the Windows utility that you can preserve your data when creating a new array. My problem: I could not recreate the arrays.

Problem number one was that the drive on Sata port 0 disappeared when you tried to create an array. All four drives looked fine in the Status view:

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but when you went to create an array, only three drives appeared:

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Following a tip from the Intel community discussion board, I removed and reinstalled the RST utility, following which I also had to reinstate the updated driver. Now the drive reappeared, but I still could not recreate the arrays. I could start creating one, but got an “unknown error.” Looking in the event log, I could see errors reported by IAStorDataMgrSvc: FailedToClaimDisks and FailedVolumeSizeCheck. Curious, especially as I had used this very same utility to create the arrays before, with the same drives and without any issues.

Just as an experiment, I booted into Windows XP 64-bit, which I still have available using Windows multiboot. I installed the latest version of the Intel storage driver and utility, and tried to create a mirror. It worked instantly. I created the second mirror. That worked instantly too. Then I booted back into Windows 7 and checked out the RST utility. Everything looks fine.

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The further good news is that I have been running with this for a few days now, without any freezes.

Is it possible that the latest driver fixed a problem? There is no way of knowing, especially since Intel itself appears not to participate in these “community” discussions. I find that disappointing; community without vendor participation is never really satisfactory.

Postscript: Note that I am aware that Intel’s embedded RAID is not a true RAID controller; it is sometimes called “fakeraid” since the processing is done by the CPU. Using Intel RST is a convenience and cost-saving measure. An alternative is Windows RAID which works well in my experience, though there are two disadvantages:

1. Intel RAID performs slightly better in my tests.

2. Windows RAID requires converting your drives to Dynamic Disks. Not a big problem, but it is one more thing to overcome if you end up doing disaster recovery.

tips

Breaking Intel RAID: what happens to your data?

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I am upgrading my desktop PC, wondering as I do if this is the last time. I did this four years ago; maybe four years from now cloud, mobile and virtualisation will make this unnecessary.

But I digress. My PC is creaking and I am replacing most of its innards. I use an Intel motherboard with its embedded RAID controller to mirror the data on the main 1TB drive. Since I am now getting new, faster drives, I want to break the RAID. The question though: will this delete all the data?

The puzzle here is that the Intel Matrix Storage Manager insists that when you delete a RAID volume, all its data is lost. But why should you lose data if you are breaking a mirrored (RAID 1) volume? In this configuration, each of two drives maintains identical data. In fact, Intel’s User’s Manual says:

All data on the RAID drives will be lost unless the volume that is selected is a RAID 1 volume.

The utility itself is less comforting though, and when I go to break the RAID it says data will be lost unless it is a “Recovery volume”, which is something slightly different.

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Now, if you are like me you set up the RAID in the first place because you would rather not lose that data. On the other hand, my suspicion was that the data would in fact be preserved. Caution prevailed, and I made a Windows system image backup of the entire thing, which took most of a day.

Then I deleted the volume. No data was lost and Windows booted perfectly, though it did reconfigure its storage drive and ask for a restart.

The second drive also retained all the data. Windows made it offline, because according to disk manager:

The disk is offline because it has a signature collision with another disk that is online

which is fair enough.

I can confirm, then, that in my experience you can delete an Intel RAID mirror without losing the data. Still, if this is data you care about, I guess you are going to take a backup anyway before pressing Y.