large file support

Bob Johnson fbsdlists at
Thu Aug 18 15:36:34 GMT 2005

On 8/18/05, Chris Knipe <savage at> wrote:
> Hi,
> Uhm, quite urgent, but does BSD support < 4GB files on i386?

Yes.  It also supports > 4 GB files.

> We have a 4.3GB MySQL Table (i.e. one file), mysql reads from it, server
> halts, we tried to cp / mv it, server halts... 
> For a test, I did a quick dd to generate a 6.4GB file, server halted.... 

I have been using dd to generate 64 GB files to test RAID
configurations with no problems.  It should support files up to at
least 2 TB, maybe more.

> What's the solution here????   

Hard to say without more details.

Did you get any error message at all, or did it just freeze?  Does
anything show in /var/log/messages?

What filesystem are you using (the default, which is UFS2, or did you
set up something else)?

How big is disk partition you are building the files on?  I.E. what
does "df" say?  Running out of disk space can cause strange problems.

Is softupdates enabled on the file system?  "tunefs -p /var" or
whatever the filesystem is will tell you.  If softupdates runs out of
memory or disk space, strange things happen.

If you run "top" while generating the 6.4 GB test file, does it show a
lot of swap being used?

- Bob

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