default inode number in large 4.3BSD filesystems

[Chris Torek]

In article <1013 at cadre.dsl.PITTSBURGH.EDU> sean at cadre.dsl.PITTSBURGH.EDU
(Sean McLinden) writes:
>A few months ago, someone posted a note stating that the default
>number of inodes created by mkfs was inadequate for large filesystems.

The problem is not large file systems *per se*; rather, if there
are many blocks per cylinder group, mkfs will generate only 2048
inodes per c.g., and you will wind up with fewer than the default
1-inode-per-2048 bytes.  In practise, I find that `user' file
systems (home directories) here at Maryland CSD work well with about
6144 bytes per inode, and `system' file systems (/usr) work well
with about 7168 bytes per inode.  The news file system at this
moment has about 5000 bytes per inode, but has had fewer than that
in the past; -i 2048 is not unreasonable for it.

>Does anyone recall what was suggested for large (~350 Mbyte), or greater
>filesystems?

After running newfs, use `df -i' to see how many inodes were
allocated; divide kbytes*1024 by ifree to see how many bytes per
inode you got.  If the number is too big, re-run newfs with an
additional `-c <n>', where <n> is less than 16.  With fewer cylinders
per group, there will be fewer blocks to divide amongst those
maximum-of-2048 inodes.

(And who ever said 350 MB was a big file system? :-) ...:

    % gyre df
    Filesystem    kbytes    used   avail capacity  Mounted on
    /dev/ra0a      38959   17038   18025    49%    /
    /dev/ra0d     585915  400419  126904    76%    /usr
    /dev/ra1d     583635  476223   49048    91%    /x
    /dev/ra2a      38751    1272   33604     4%    /betaroot
    /dev/ra2d     585915  440761   86562    84%    /betausr

)
-- 
In-Real-Life: Chris Torek, Univ of MD Computer Science, +1 301 454 7163
(still on trantor.umd.edu because mimsy is not yet re-news-networked)
Domain: chris at mimsy.umd.edu		Path: ...!uunet!mimsy!chris