4 more questions about RAID

Longtime reader Jim ` asked me a few more worthwhile questions while I was procrastinating working on yesterday’s post about RAID. Let’s go to Q&A format.

Q: Does the choice of file system formatting make any difference when one is creating a RAID 1 array? And what are the pros and cons to using FAT32 vs. NTFS?

A: Interesting question. Overall, no, the filesystem doesn’t make any difference. To the filesystem, the RAID array is just a storage device, and to the RAID array, the filesystem is just data.

FAT32 is a simpler filesystem, so yes, recovery can be easier. But NTFS is more robust, so you’re less likely to have problems in the first place. In the days when having to use a DOS boot disk was common, I could see doing FAT32. But now that Linux live CDs can read and write NTFS, and you can even make a Windows live CD with BartPE, I’m more willing to just use NTFS for everything, unless permissions get to be an issue. But even then, you can just set permissions to “Everyone/Full Control” to replicate FAT’s behavior.

I’m still convinced there was a time when FAT gave a performance advantage over NTFS–one dirty trick Microsoft used to do in the marketing they sent to CIO types was to benchmark Windows 2000 against NT4 and use NTFS on the NT4 box but FAT32 on the Windows 2000 box, then brag about how much faster Windows 2000 was on identical hardware–but these days, a 2 GHz 2-core CPU is considered low end and the extra cores spend much of their life looking for things to do, so, that’s pretty much negated that.

The only time I use FAT32 anymore is on removable media. My DVD player has a USB port. My TV has an SD port. And my digital cameras are SD. But they all use FAT32. So I keep my SD and USB flash devices formatted FAT32.

But I wouldn’t anticipate anyone taking half of a RAID array, sticking it into a USB enclosure, and connecting it to a DVD player.

Q: If all I really want is backup in case of emergency, is there any reason to install Intel’s RST or Marvell’s software? Overheard is high and Windows takes a long time to boot with the software installed.

I can create an array using just the controllers, can’t I?

A: Yes you can. The benefit of installing the software usually is to get notification that one of the drives in the array has failed. You can live without it, but then the only way to know you have a failed drive is when you do your monthly reboot for installing patches.

Q: My motherboard has an Intel P55 RAID controller with 6 ports. I’m currently using two: one for an optical drive, and another as a single Dump drive for archival stuff. Can I create an RAID_1 array using just 2/6 ports on that controller and keep the other ports open for single drives?

A: I don’t know about the Intel P55 specifically, but most RAID controllers will allow you to do that.

Q: Assuming I install WinXP using the F6 routine with the RAID/AHCI controllers set to AHCI mode, will Windows have a spasm if at a later date I decide to switch one or both controllers to RAID mode?

A: If you’re not booting off the array, Windows won’t care. You can do anything you want with data drives. Windows often doesn’t like you messing with the boot drive. If you convert a boot drive to or from RAID, you should be OK, but I can see the potential for issues if the way the controller addresses an array differs from how it addresses an individual disk. Have a backup copy and be prepared to reinstall if you decide to convert a boot drive to or from RAID.

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