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From: "Miquel van Smoorenburg" <miquels@cistron.nl>
Subject: Re: a 15 GB file on tmpfs
Date: Wed, 20 Jul 2005 13:35:07 +0000 (UTC)
Organization: Cistron
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References: <200507201416.36155.naber@inl.nl> <20050720132006.GI7050@harddisk-recovery.com>
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In article <20050720132006.GI7050@harddisk-recovery.com>,
Erik Mouw  <erik@harddisk-recovery.com> wrote:
>On Wed, Jul 20, 2005 at 02:16:36PM +0200, Bastiaan Naber wrote:
>> I have a 15 GB file which I want to place in memory via tmpfs. I want to do 
>> this because I need to have this data accessible with a very low seek time.
>
>That should be no problem on a 64 bit architecture.
>
>AFAIK you can't use a 15 GB tmpfs on i386 because large memory support
>is basically a hack to support multiple 4GB memory spaces (some VM guru
>correct me if I'm wrong).

I'm no VM guru but I have a 32 bit machine here with 8 GB of
memory and 8 GB of swap:

# mount -t tmpfs -o size=$((12*1024*1024*1024)) tmpfs /mnt
# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1             19228276   1200132  17051396   7% /
tmpfs                 12582912         0  12582912   0% /mnt

There you go, a 12 GB tmpfs. I haven't tried to create a 12 GB
file on it, though, since this is a production machine and it
needs the memory ..

So yes that appears to work just fine.

Mike.