Adding/setting up mem, disk, cd drive, sys admin?
Alan's Home for Wayward Notes File.
alan at shodha.enet.dec.com
Sun Jun 16 16:47:44 AEST 1991
In article <44675 at netnews.upenn.edu>, lau at desci.wharton.upenn.edu (Yan K. Lau) writes:
> I added 2 RZ57s in an expansion unit to the system. I ran MAKEDEV and
> newfs. The results were about 950megs total with 850megs available. Is
> this normal? I read somewhere that the system takes about 10% for
> (mumble...mumble).
And I responded "This seems to be normal". But just to be
sure I tried an experiment. We also have a new expansion
box with two RZ57s in it with which I've been able to experi
ment. The df(1) output for a new file system looks like:
Filesystem Total kbytes kbytes %
node kbytes used free used Mounted on
/dev/rz1c 945726 9 851145 0% /mnt
Clearly the amount free and the amount used don't add up
to the total. If we take 10% off the total first though:
945,726 - 94,572 = 851,154 = 851,145 + 9
So it does work out. What happens as the file system fills?
I don't have the intermediate steps handy, but I do have the
end result:
Filesystem Total kbytes kbytes %
node kbytes used free used Mounted on
/dev/rz1c 945726 945726 0 111% /mnt
The "kbytes free" went to 0 the same time the %used went to
100%. After that "free" continued to be zero as I slowly
filled up the rest of the disk. So a completely full file
system will end up at 111% full, which makes sense when you
think about it.
Finally; getting that last few blocks used up wasn't easy.
I create a bunch of large files initially by making copies
of /dev/mem into the file system. When I got enough of those
I made a another that took up most of the rest and slowly
appended stuff onto the end of it until I got file system
full messages. At this point I had just a few KB left over.
These last few I picked up by creating an appropriate number
of small files of 1 KB each. I still had lots of inodes left
though.
--
Alan Rollow alan at nabeth.cxn.dec.com
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