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Date: Wed, 14 Sep 2005 13:20:45 -0700
To: dmarshall@gmail.com, freebsd-questions@freebsd.org
From: Glenn Dawson <glenn@antimatter.net>
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Subject: Re: File-Backed Memory Disks: Performance and Manipulation
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At 12:44 PM 9/14/2005, David Marshall wrote:
>Hi,
>
>Scenario: We have millions of little (almost all < 10 kB), about 30 GB
>total.  It takes > 24 hours to either tar them up or then untar them.
>It finally occured to us to put them into a file-backed memory disk.
>
>Questions:
>
>1. How does the performance of a file-backed memory disk change as it
>becomes large?
>
>2. Is there a clever way to make such a file-backed memory disk bigger
>after the fact?  If I want to expand my 30 GB file to 50 GB, am I
>stuck with just making a new one and copying it over?

I've done that by concatenating an empty file of the size I wish to 
add on to the end of the existing backing store file, editing the 
disk label and then using growfs to expand into the new space.

-Glenn


>TIA!
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