large disk > 8 TB

Mark Carlson carlsonmark at
Tue Dec 11 15:18:43 PST 2007

On 12/11/07, Ivan Voras <ivoras at> wrote:
> Michael Fuckner wrote:
> > Lan Tran wrote:
> >> I have a Dell PERC 6/E controller connected to an external Dell MD1000
> >> storage, which I set up RAID 6 for.  The RAID BIOS reports 8.5 TB.  I
> >> installed 7BETA4 amd64 and Sysinstall/dmesg.boot detects this correctly:
> >> mfid1: <MFI Logical Disk> on mfi1
> >> mfid1: 8578560MB (17568890880 sectors) RAID volume 'raid6' is optimal"
> >>
> >> However, after I created a zfs zpool on this device it only shows 185
> >> GB. # zpool create tank /dev/mfid1s1d
> >> # zpool list
> >> NAME                    SIZE    USED   AVAIL    CAP  HEALTH     ALTROOT
> >> tank                    185G    111K    185G     0%  ONLINE     -
> >>
> >> also with 'dh':
> >> # df -h tank
> >> Filesystem    Size    Used   Avail Capacity  Mounted on
> >> tank          182G      0B    182G     0%    /tank
> >>
> >
> > The main purpose of ZFS is doing Software raid (which is even faster
> > than HW Raid nowadays).
> >
> > You should export all disks seperately to the OS- and then you don't
> > have the 4GB limit wrapping the size to 185GB.
> This is the wrong way around. Why would something wrap drive sizes at a
> 32-bit limit? The driver and the GEOM systems are 64-bit clean, if this
> is a problem in ZFS, it's a serious one.
> I don't have the drive capacity to create a large array, but I assume
> someone has tested ZFS on large arrays (Pawel?)

If there is a bug here, I'm not sure people will see it for a while in
practice.  I mean, who is using hardware raid to create a 8.5GB "disk"
then create a zpool with that one "disk"?

In this case, it appears there was some misconfiguration that has been
remedied: hardware raid seems to have been disabled now, and all the
disks are exported seperately to create a zpool with, resulting in

> Can you run "diskinfo -v " on the large array (the 8.5 TB one) and
> verify the system sees it all?

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