From: Dave Chinner <david@fromorbit.com>
To: david@lang.hm
Cc: xfs@oss.sgi.com
Subject: Re: 128TB filesystem limit?
Date: Fri, 26 Mar 2010 11:35:11 +1100 [thread overview]
Message-ID: <20100326003511.GN3335@dastard> (raw)
In-Reply-To: <alpine.DEB.2.00.1003251702190.12435@asgard.lang.hm>
On Thu, Mar 25, 2010 at 05:03:52PM -0700, david@lang.hm wrote:
> On Fri, 26 Mar 2010, Dave Chinner wrote:
>
> >On Thu, Mar 25, 2010 at 04:15:42PM -0700, david@lang.hm 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@fromorbit.com
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next prev parent reply other threads:[~2010-03-26 0:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-25 23:15 128TB filesystem limit? david
2010-03-25 23:54 ` Dave Chinner
2010-03-26 0:03 ` david
2010-03-26 0:35 ` Dave Chinner [this message]
2010-03-26 2:02 ` david
2010-03-26 4:35 ` Eric Sandeen
2010-03-26 4:56 ` david
2010-03-26 6:09 ` Stan Hoeppner
2010-03-26 7:26 ` Steve Costaras
2010-03-27 9:06 ` Emmanuel Florac
2010-03-27 14:28 ` Steve Costaras
2010-03-27 18:45 ` david
2010-03-28 21:17 ` Peter Grandi
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