Date: Tue, 13 Oct 1998 11:44:10 +0930 From: Greg Lehey <grog@lemis.com> To: Terry Lambert <tlambert@primenet.com>, francisco@natserv.com Cc: freebsd-fs@FreeBSD.ORG Subject: Re: Optimizing space utilization Message-ID: <19981013114410.A21983@freebie.lemis.com> In-Reply-To: <199810122018.NAA21730@usr07.primenet.com>; from Terry Lambert on Mon, Oct 12, 1998 at 08:18:53PM %2B0000 References: <199810110304.XAA22392@federation.addy.com> <199810122018.NAA21730@usr07.primenet.com>
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On Monday, 12 October 1998 at 20:18:53 +0000, Terry Lambert wrote:
>>>> On a 1 Gig partition by using 1/4 the number of inodes (sent -i 16384
>>>> to newfs) I was able to save a little over 30MB. A 3% saving. :-)
>>>> I was still left with over 64K inodes, which I doubt I will use.
>>
>>> Interesting. At 262 bytes per inode, I'd only expect a saving of
>>> about 12 MB.
>
> Uh, what are you smoking?
Cooked inodes.
> An inode is 128 bytes, exactly, including reserve space.
Oops. The in-core inode is 262 bytes, which isn't particularly
relevant to the disk. Where should I have been looking (i.e. which
file?).
> Are you perhaps counting the mandatory 24 byte overhead on a directory
> entry, and assuming a 110 byte file name? If so, you should be
> aware that flexname allocations must round to 4 byte boundaries,
> so you are off by 2 (108 and 112 are evenly divisible by 4).
No. Here's a test program:
#define MAXQUOTAS 2
#include "/T/vinum/vinumhdr.h"
#include <ufs/ufs/inode.h>
main ()
{
printf ("inode size is %d\n", sizeof (struct inode));
}
The MAXQUOTAS is because I didn't want a whole slew of knotted header
files. vinumhdr is gratuitous, but save more knotted header files.
Greg
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