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SB850 Ma Dive Size

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August 27, 2011 5:01:14 PM

Hello,

I just had a computer built for me that has an Asus M487TD Pro mother board. That motherboard uses the SB850 chipset and I am having a problem with it. I had the machine maxed out with 6 3T Hitachi drives but sometimes the motherboard recognizes these drives and sometime it doesn't. Even when it does, when I try to create a RAID 5 array in the BIOS, it tells me that the drives are a bit over 800G in size, not 3T.

My question is: Is 3T beyond the capacity of the SB850 chipset? Has anyone successfully used 3T drives either as single boot drives or in a RAID array?

Thnaks for any help on this.

More about : sb850 dive size

a b V Motherboard
a c 302 G Storage
August 27, 2011 11:16:56 PM

I may be introducing a red herring, but FWIW AMD's SB850 southbridge has problems with certain Samsung HDDs.

https://ata.wiki.kernel.org/index.php/Known_issues

As for the capacity problem, it does appear to be a 2TiB limitation problem:

3TB - 2TiB = (3 x (10^12)) - (2 x (1 024^4)) = 800 976 744 448
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August 30, 2011 4:41:44 PM

I don't think that is a red herring at all -- I suspect that you have hit the nail on the head. Now I just have to figure a way out of this mess :-) Any idea what mother board will support 3T drives and an AMD AM3 CPU?

Thanks
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a b V Motherboard
a c 302 G Storage
August 30, 2011 8:47:05 PM

Sorry, I haven't looked at a new motherboard for several years now. That's something for other members to suggest.

That said, I would investigate any BIOS update options before opting for a new motherboard.
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August 30, 2011 10:27:33 PM

That's possible but remember that this is a new build. Everything's brand new so I would assume that if the BIOS isn't the absolute latest, it should be pretty close.
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September 6, 2011 2:42:38 AM

I am beginning to suspect the chipset here. After the disappointment with the 3T drives, the builder replaced the drives with 2T units, created a RAID 5 array and partitioned the array to have a 500G system drive and the rest as a data drive. I ran into problems with that because the array presented the larger disk as having 4K sectors and a lot of software (HyperV included) cannot tolerate 4K sectors. But, I noticed that a) the 500G drive presented itself with 512Byte sectors and b) I checked the disks and they have 512Byte sectors. So, the only thing I can figure is that the SB850 chipset must repackage the data for large drives in 4K sectors. Does that sound reasonable? I know that it blows me out of the water because all of the software I want to run on that box will only accept 512Byte sectors.
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a b V Motherboard
a c 302 G Storage
September 6, 2011 8:37:56 AM

I don't have any significant RAID knowledge or experience, but ISTM that the RAID controller's firmware (ie RAID BIOS) would be doing the repackaging. I doubt that it would be happening at the hardware level within the chipset.

FWIW, I know that some external 3TB HDDs (eg Seagate 3TB GoFlex) present a 4KB LBA size via USB, even though the drive itself reports an LBA size of 512 bytes. In the GoFlex case the USB-SATA bridge chip handles the translation. I believe Seagate chooses to do it this way in order to support Windows XP straight out of the box.

Have you checked the configuration options in your RAID BIOS?
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September 10, 2011 7:33:16 PM

It is almost definately the RAID chipset. When I first started this thread, I was configuring the RAID with 2 drives: one 500G and one 9.5T (6 2T drives in the array). Both drives were RAID 5 and they spanned all 6 drives. When I installed Windows, it saw the 500G drive as having 512 Byte sectors and the 9.5T drive as having 4K sectors. Since that configuration was no good for me, I changed the RAID to have the first 2 drives mirrored and the last 4 configured as RAID 5. After installing Windows, I checked and found the 2T mirrored drive had 512 Byte sectors and the larger drive had 2K sectors.

Bert
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