Subject: Re: tuning TB RAID-backed filestore to reduce inode/superblock overhead
To: George Michaelson <email@example.com>
From: Luke Mewburn <lukem@NetBSD.org>
Date: 09/07/2004 12:06:32
Content-Type: text/plain; charset=us-ascii
On Tue, Sep 07, 2004 at 11:36:38AM +1000, George Michaelson wrote:
| Is there a HOWTO for BSD which explains what is 'reasonable'
| overhead to work towards in constructing a 1.5Tb filestore on RAID?
| A co-worker just complained the consumed space for 1.5tb looked to
| be 100Gb and that seems a very high overhead. -no tunefs, no newfs
| options, no RAID tuning. Out of the box.
That sounds rather high.
| Any simple guidance would be appreciated.
It depends on how many files (inodes) that you expect to store on=20
You can gain more space back by increasing:
-b block size
-f frag size
-i bytes per inode
and by decreasing the
-m free space %
You can also get an idea of the metadata overhead of the cylinder
groups and inodes by newfs'ing a file (newfs -F -s somesize ...)
and du-ing the result. Don't forget to rm the test file between
runs. (Just don't use -Z to pre-zero all blocks during testing :)
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