LinuxQuestions.org - 18TB logical volume

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18TB logical volume

Is it passable to create a logical volume of 18TB in size? I was able to create the volume group but I’m having issues with the logical volume.

This probably doesn't belong in the Newbie forum. Newbies shouldn't be using LVM, especially on real projects (18TB sounds pretty real).

Quote:

Originally Posted by ccampbell@etcc.com (Post 4177686)

I was able to create the volume group but I’m having issues with the logical volume.

What is it telling you? Specific error messages lead to better answers.

The following might help, but is not authoratative: http://www.walkernews.net/2007/07/02...volume-in-lvm/

Quote:

Beside the PE size, the maximum size of single LV is also limited by CPU architecture and Linux kernel version:

* Linux kernel version 2.4.x limit the maximum LV size to 2TB.

* Some older Linux kernel prior to 2.4.x, the maximum LV size is limited to 1TB (caused by the integer signedness problems in the block layer).

* The combination of 32-bit CPU and Linux kernel version 2.6.x, the limit of logical volume size is maximized at 16TB.

* For Linux kernel 2.6.x running on 64-bit CPU, the maximum LV size is 8EB (extremely terrible big storage for this time being!)

"uname -a" might give us some of these clues. I suspect that third bullet point might be your concern...

Thanks for your reply,
I have been trying to resize the PE but I must be doing something wrong.

uname -a
Linux server_name.local 2.6.18-194.26.1.0.1.el5 #1 SMP Tue Nov 9 18:48:15 EST 2010 x86_64 x86_64 x86_64 GNU/Linux

This is the error i get when creating new logical Volume....
Creation of filesystem failed. Command attempted: "/sbin/mkfs -t ext3 /dev/backupgroupVol3/vol3" - System Error Message: mke2fs 1.39 (29-May-2006)mkfs.ext3: Size of device /dev/backupgroupVol3/vol3 too big to be expressed in 32 bits using a blocksize of 4096.

ext3 doesn't support devices larger that 2 TB, you should move to another file system that does (ext4,ocfs2,xfs,zfs,btrfs,...)

I tried ext3, I have to figure out how to get the other file systems configured.

Creation of filesystem failed. Command attempted: "/sbin/mkfs -t ext4 /dev/backupgroupVol3/vol3" - System Error Message: mke4fs 1.41.9 (22-Aug-2009)mkfs.ext4: Size of device /dev/backupgroupVol3/vol3 too big to be expressed in 32 bits using a blocksize of 4096.

Hmm, sorry about suggesting ext4. It looks like the file-system structure now supports larger than 16 TB size but the tools to create one don't yet.

That's a problem. I'd try one of the other file systems mentioned. It is, however, possible to expand ext3 up to at least 16TB by increasing the block size to 4K.

4K also appears to be the limit for ext4 on x86 (and presumably x86-64). I suspect that is what causes the 16TB limit on ext4, but I'm not sure. It might be worth playing with.

If your project lends itself to it, you might consider making 2 LV.