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Raid Setup Help

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June 8, 2009 9:49:35 AM

Mobo: Intel Desktop Board D5400XS

Question 1) I currently have (4) WD VelociRaptor 300GB drives setup with (2) RAID0's using OnBoard RAID. I Just got ASR-5405 RAID Card and want to know the steps to upgrade from my current setup. Install software first?Disable onbaord RAID? Can I use my same RAID setup? etc

Question2) The current hard drives I have installed, the WD VelociRaptor's will this RAID card allow me reach max speeds?

More about : raid setup

a b G Storage
June 8, 2009 10:02:23 AM

Your current RAID 0 mbr will not be compatible with Adaptec ASR-5405, you will have have to start over.

Here's the steps:
1)Back all up your personal data
2)Grab the latest drivers for your components and store it on a USB flash drive
3)Move the two(or four depending on what you want) VelociRaptors to the Adaptec card, replace HDD for boot order in BIOS(of the motherboard) with something along the line of 'SCSI card'.
4)Go into the BIOS of the Adaptec card during POST and set up your new RAID 0(or 10) array. At this stage ALL your data will be erased.
5)Precede to install Windows and provide the Adaptec's controller driver to see your newly created array
6)Format it
7)Windows is installed and you can precede to install the drivers. Starting with driver for Intel chipset.

Remember with four HDDs you can run RAID 10, but you lose half of the total space to gain redundancy.
a c 127 G Storage
June 8, 2009 1:23:50 PM

You should indeed backup your files. But it should be possible to re-create the RAID with the same parameters (RAID level, disk order, stripesize, offset), and you should be able to access your files. For this to work with Windows, you need to install the hardware RAID driver first.

If it works, it saves you the work of restoring the files and re-installing the operating system.
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a b G Storage
June 8, 2009 9:41:06 PM

Quote:
But it should be possible to re-create the RAID with the same parameters (RAID level, disk order, stripesize, offset), and you should be able to access your files. For this to work with Windows, you need to install the hardware RAID driver first.

I assume this work on non-parity arrays only? e.g. 0, 1, 0+1 and 10
And is it only between certain controllers?

Would be great to learn something new. Thanks.
June 9, 2009 3:17:01 AM

rrob -- (1) Assume you have to start from scratch and install/restore everything as wuzy suggested, unless you're willing to do a bit of experimenting as sub mesa suggested.

(2) Yes, you are likely to get quite good performance with that setup, and the Adaptec is definitely a step up from the Intel ICHR. (I hope you bought the BBU for the Adaptec?) However, RAID-0's benefit is improved sustained xfer rate; if that isn't your performance bottleneck (and it rarely is), you're unlikely to see much of a real-world performance improvement.

(3) Assuming, based on your previous posts, that you're trying to get a performance improvement in a heavy VM environment, I think you're going to be a bit disappointed (RAID-0 is not the solution to that problem, unless you have very weird workloads). RAID-1, or better RAID-10 (assuming you can afford the loss of disk space), would likely be preferrable, especially with a decent controller such as the Adaptec and with BBU cache.


sub mesa -- Neat trick if it works, and easy enough to test. Assuming one of those RAID-0 arrays is what rrob is booting from, it'll either boot or it won't once he's created the array in the Adaptec BIOS. My guess is it won't, but I'd be happy to be proved wrong.

Have you seen it work or this theory? I ask because I'm very skeptical based on past experience (at least with LSI). Not to mention that it would require that the Intel and Adaptec metadata are compatible, and placed in compatible physical locations on the drives in the array so they don't step on anything else important, and that the resulting on-disk-structure was also block-for-block compatible. RAID-1? Maybe. RAID-0? Unlikely. Anything other RAID (except maybe RAID-4)? A snowball's chance.

OTOH, it's an interesting thought... would be cool if Intel and another vendor were to get together and make their metadata compatible so there was a nice and easy upgrade (or downgrade) path.
a c 127 G Storage
June 9, 2009 10:29:02 AM

Yes i've tried this. In fact, i've recovered many onboard RAID / hardware RAID this way, using linux/BSD software RAID drivers. The Freebsd geom_stripe can also be used without even writing the metadata sector, so you can try RAID-configurations without one single modification to the harddrive contents. For example trying several stripesizes. Because most RAIDs store the configuration in the last sector, the on-disk storage layout is the same, and thus you should be able to re-create the array and have access to your data.

The only reason it wouldn't work is:
- 1) you recreate with the wrong settings (disk order is something you cannot change, also sometimes you have to guess the stripesize
- 2) some implementations might be using an offset different than 0 (rare) or store the metadata in another location, for example the first sector (never seen in the wild)
- 3) when deleting/creating an array, a BIOS setup utility may also choose to overwrite the first 20MB with zeroes, just like a format of NTFS filesystem does. In this case, you loose the first 20MB of data, which often contains important filesystem info.
!