# 2tb limit?



## wjones (Jan 15, 2009)

im trying to install freebsd 7.1 on an x86 machine with a 4.5tb 3ware raid array. however when i use one large slice it wont boot, and if i use a smaller slice for the os (~20gig) then create a seperate slice for the remaining space, it boots however despite fdisk and disk label saying this mountpoint should be ~4tb it comes up as ~1.8tb. is there a work around for this?


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## kamikaze (Jan 15, 2009)

This is actually not a file system issue, but an issue with the ancient partitioning scheme. You can use gpt to create a modern partitioning scheme without this limitation. Efi used to be required for booting from it, but with 7.1 this requirement is supposed to be gone.


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## SirDice (Jan 15, 2009)

wjones said:
			
		

> im trying to install freebsd 7.1 on an x86 machine with a 4.5tb 3ware raid array. however when i use one large slice it wont boot, and if i use a smaller slice for the os (~20gig) then create a seperate slice for the remaining space, it boots however despite fdisk and disk label saying this mountpoint should be ~4tb it comes up as ~1.8tb. is there a work around for this?



I wouldn't use one big slice anyway :e

But.. UFS should be able to handle quite a lot more.. So I find it odd it 'sees' only 1.8TB :\


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## SirDice (Jan 15, 2009)

kamikaze said:
			
		

> This is actually not a file system issue, but an issue with the ancient partitioning scheme. You can use gpt to create a modern partitioning scheme without this limitation.


Forgot about that :r


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## wjones (Jan 16, 2009)

kamikaze said:
			
		

> This is actually not a file system issue, but an issue with the ancient partitioning scheme. You can use gpt to create a modern partitioning scheme without this limitation. Efi used to be required for booting from it, but with 7.1 this requirement is supposed to be gone.



Thanks for the tip, I mulled over this thread (http://forums.freebsd.org/showthread.php?p=8432) and finally got it working. :beergrin



			
				SirDice said:
			
		

> I wouldn't use one big slice anyway :e
> 
> But.. UFS should be able to handle quite a lot more.. So I find it odd it 'sees' only 1.8TB :\



I was just trying different stuff to make it work; I wouldnt want a single partition that big either. I was also aware that ufs2 has a great deal of capacity, which is why this puzzled me. Hopfully they get this worked out in the near future, sure is alot of trouble to install backup parition restore... :\


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## Christopher (Jan 16, 2009)

SirDice said:
			
		

> But.. UFS should be able to handle quite a lot more.. So I find it odd it 'sees' only 1.8TB :\



UFS2 does, but an MBR style partition cannot be bigger than 2TB in size due to using 32-bit counters.  In this case I suspect the counter overflowed and "warped around", so the system thought the partition was only 1.8TB in size.


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## aragon (Jan 22, 2009)

It sounds like you want to dedicate the entire array to FreeBSD, so maybe you should try creating a "dedicated" slice during installation?  During installation, delete all existing partitions, press "F" and choose "No" at the following warning prompt.

That will create a single, dedicated slice on the disk that I imagine will allow you access to the entire 4.5 GB.  No MBR is created so your array will be inaccessible from other OSes.


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## wjones (Jan 22, 2009)

aragon said:
			
		

> It sounds like you want to dedicate the entire array to FreeBSD, so maybe you should try creating a "dedicated" slice during installation?  During installation, delete all existing partitions, press "F" and choose "No" at the following warning prompt.
> 
> That will create a single, dedicated slice on the disk that I imagine will allow you access to the entire 4.5 GB.  No MBR is created so your array will be inaccessible from other OSes.



I tried this with no success early on. I dont see anyway around it; gotta use guid partition table to go over 2tb and afaik the only way to do this is with gpt.


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## graudeejs (Jan 22, 2009)

it's also possible to make guid partitions with gpart, but i haven't explored that area.

but if you google, you'll find howtos on net


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## hedwards (Jan 27, 2009)

wjones said:
			
		

> I tried this with no success early on. I dont see anyway around it; gotta use guid partition table to go over 2tb and afaik the only way to do this is with gpt.


I'd just use GPT, it's not actually that tough to use, a little bit of oddness in terms of creating a specific MBR partition, but not tough at all.

It is worth noting that you're probably not going to want to use UFS2 for a 2tb disk. I mean you can do so, but large disks get corrupted very easily and there are serious concerns about data integrity. It'd probably be better to use something like ZFS, if only for /usr.

Not that UFS2 is necessarily bad, but it takes a while to fsck when you need to and ZFS doesn't suffer the way that UFS2 and most other FSes do when you have a panic or lose power.


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## dh (Jan 27, 2009)

You could use gjournal with UFS to help with long fsck times in case UFS corruptions (due to disk failures). But I assume you use somekind of RAID setup so I don't see why that would be an issue unless you have power problems.
I have 5.4TB UFS filesystem and there has never been any problems.


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