On Thu, Mar 25, 2010 at 05:03:52PM -0700, david@xxxxxxx wrote:
> On Fri, 26 Mar 2010, Dave Chinner wrote:
>
> >On Thu, Mar 25, 2010 at 04:15:42PM -0700, david@xxxxxxx wrote:
> >>I'm working with a raid 0 (md) array on top of 10 16x1TB raid 6
> >>hardware arrays.
....
> >>I then did mkfs.xfs /dev/md0
> >>
> >>but a df is showing me 128TB
> >
> >What is in /proc/partitions?
>
> # cat /proc/partitions
> major minor #blocks name
>
> 8 0 292542464 sda
> 8 1 2048287 sda1
> 8 2 2048287 sda2
> 8 3 2048287 sda3
> 8 4 286390755 sda4
> 8 16 13671874048 sdb
> 8 17 13671874014 sdb1
> 8 32 13671874048 sdc
> 8 33 13671874014 sdc1
....
> 8 160 13671874048 sdk
> 8 161 13671874014 sdk1
> 9 0 136718739840 md0
Is there any reason for putting partitions on these block devices?
You could just use the block devices without partitions, and that
will avoid alignment potential problems....
> >>is this just rounding error combined with the 1000=1k vs 1024=1k
> >>marketing stuff,
> >
> >Probably.
> >
> >>or is there some limit I am bumping into here.
> >
> >Unlikely to be an XFS limit - I was doing some "what happens if"
> >testing on multi-PB sized XFS filesystems hosted on sparse files
> >a couple of days ago....
>
> Ok, 128TB is a suspiciously round (in computer terms) number,
> especially when the math is 10 sets of 14 drives (each 1TB), so I
> figured I'd double check.
136718739840 / 10^9 = 136.72TB <==== marketing number
136718739840 / 2^30 = 127.33TiB <==== what df shows
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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