Date: Thu, 28 Oct 1999 02:33:22 -0700 (PDT) From: Julian Elischer <julian@whistle.com> To: peter.jeremy@alcatel.com.au Cc: freebsd-arch@freebsd.org Subject: Re: Storing small files in inodes Message-ID: <Pine.BSF.4.10.9910280018120.10856-100000@current1.whistle.com> In-Reply-To: <99Oct28.135145est.40328@border.alcanet.com.au>
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These are called nanofiles. Bill Jolitz talked about them in a talk he did on BSD in '91 In effect we already do that.. note how malloc(3) uses a symlink to read its config info :-). On Thu, 28 Oct 1999, Peter Jeremy wrote: > I'd like to float the possibility of storing small (<= 60 bytes) files > and maybe directories inside inodes, in the same manner as short > symlinks are stored. > > Looking through my main system, about 12.5% of inodes are allocated > to short files and a further 3.5% are allocated to short directories. > > Advantages: > - Faster access to the file (since the inode contains the contents, > rather than a pointer to the contents). > - In my case, saving about 1.3% of disk space though this would > increase if I moved to a larger fragment size. > > Disadvantages: > - Filesystem media incompatability we'd have the code to read it turned on by default for 6 months before we turned on the default to write them. > > Programs affected (based on the programs that have special handling > for symlinks via MAXSYMLINKLEN or fs_maxsymlinklen): > - fsck(8), fsdb(8) and dump(8) > - libstand/ufs.c > > The kernel handling would be more complex than for symlinks because > files additionally have the ability to be mmap'd and updated, but I > don't believe the problems are insurmountable. > > Comments? I vaguely remember a paper on the topic. Maybe kirk can tell us more. > > Peter > -- > Peter Jeremy (VK2PJ) peter.jeremy@alcatel.com.au > Alcatel Australia Limited > 41 Mandible St Phone: +61 2 9690 5019 > ALEXANDRIA NSW 2015 Fax: +61 2 9690 5982 > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-arch" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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