[linux-lvm] LVM limit on PE's/size?

[Andreas Dilger]

On Nov 27, 2001  11:34 -0600, Scott P wrote:
> We are planning to add a 3 rd EXP300 array to out current server w/ 2
> EXP300's in place already!  We WILL surpass the 1 TB size, if possible?

Depends if the driver does 32-bit block numbers with signed or unsigned
values.  The absolute maximum supported by 2.4 kernels is 2TB devices.
I don't know if 2.2 will support > 1TB devices, but it is possible.

> Linux ptb3 2.2.19 #2 SMP Tue Jul 24 11:53:29 CDT 2001 i686 unknown
> 
> We are using:
> lvm_0.9.1_beta7
> reiserfsprogs-3.x.0j

Get newer LVM tools, like 1.0.1, because the old ones have lots more bugs.
Beta 7 has the PE alignment bug, so you should upgrade the tools even if
you can't upgrade the kernel.

> Here is the current filesystem and size:
> 
> /dev/exp300_2/exp300_lv2 924160464 891307744  32852720      97% /files1

> Q: Why are my logical volumes limited to 256 GB in size?
> A: This is NO absolute limit but it depends on the physical extent size
> you configured at volume group creation time.

Check what "pvdata -P /dev/whatever" tells you about the PE size.  If
it is 16386kB, then you are limited to 1TB in size.  If it is larger
than that, you _may_ be able to go past 1TB, but you may not, depending
on whether your drivers and kernel work properly or not.

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/