LVM Maximum Volume Size?

[Georgios Magklaras]

On 02/16/2011 07:16 PM, Matty Sarro wrote:
> Out of curiousity, what is the maximum size volume that LVM can
> handle? I know that it sits as a wedge between the actual logical
> volume the system sees, and the hardware. Is there a limit?
>
> At the moment we are looking at a maximum storage of 72TB for log
> storage. My planned approach is to create a separate LUN and
> disk-group for each folder on our log server, and then create a
> logical volume and mount it under the FTP/NFS server's directory. Then
> as more storage is needed, simply create a new LUN on the SAN, add it
> as an LVM disk in the disk group for that particular folder, and let
> LVM handle growing the logical volume. Is it bound to the same disk
> max size as EXT3 (16TB)? Or is there another barrier to worry about?
>
> Am i misunderstanding the capabilities of LVM?
>

When considering storage at large quantities, the thing you have to 
start from is what happens at the logical volume level, where you have 
the filesystem. I believe that RHEL's ext3 and ext4 are still on a 16 TB 
per filesystem (aka logical volume) limit. If you wish to go larger per 
logical volume/filesystem, in RHEL you need to look at XFS. In RHEL 6, 
an XFS filesystem is supported up to 100 Tbytes.

To answer your original question, LVM2 on an 64bit CPU and a 2.6 kernel 
can support up to 8EB per single LV. So, the limit is not LVM but your 
filesystem choice.

GM


-- 
-- 
George Magklaras
Senior Systems Engineer/IT Manager
Biotek Center, University of Oslo
EMBnet TMPC Chair

http://folk.uio.no/georgios

Tel: +47 22840535