Gentoo Archives: gentoo-user

From: Iain Buchanan <iaindb@××××××××××××.au>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] 320GB hard drive maxed at ~280GB?
Date: Wed, 25 Oct 2006 04:53:27
Message-Id: 1161751643.22203.19.camel@orpheus
In Reply to: [gentoo-user] 320GB hard drive maxed at ~280GB? by Grant
1 On Tue, 2006-10-24 at 21:12 -0700, Grant wrote:
2 > I have a 320GB hard drive
3
4 yes, a 320 "gigabyte" hard drive, as opposed to a 320
5 "gibibyte"[1][2][3] hard drive. Technically 1 gigabyte is one million
6 bytes, but computers have always used 1GB = 1024kB = 1024*1024B.
7
8 Hard drive manufacturers use the SI gigabyte, whereas computers use the
9 globally accepted (but technically incorrectly named) computer gigabyte.
10 So you really only have 320,000,000 bytes = ~ 305GB.
11
12 But wait, there's more...
13
14 > with a small swap partition,
15
16 lets say, 500MiB
17
18 > a small boot partition,
19
20 lets say, 10MiB
21
22 > and the remainder in the root partition.
23
24 that leaves you 305 - 0.5 - 0.01 = ~ 304 (conservatively)
25
26 > 'du -sh /' says
27 > 278G and a mkisofs command failed with no space left on device. What
28 > happened to the rest of the gigs?
29
30 The rest of it goes in:
31 - filesystem overheads (every filesystem suffers. some more than
32 others. someone else on this list may like to comment more on my lack
33 of knowledge here)
34
35 - in Linux, a small % of the filesystem is reserved for root - this is
36 so that an unprivileged user (or core dump, or erroneous program) cannot
37 fill the filesystem 100% and stop even root from logging in. I think
38 it's about 3% by default on ext3? (just guessing. It may even default
39 to a fixed number of blocks - not sure). This can be configured when
40 you run mkfs. On such a large drive, you may want to drop this down to
41 1% or smaller.
42
43 Try `df -h` and see what it says. See if the difference is really all
44 that great. If so, there may be other reasons you have less than you
45 think...
46
47 HTH!
48
49 [1] http://en.wikipedia.org/wiki/Gibibyte
50 [2] http://www.answers.com/topic/gibibyte-1
51 [3] http://physics.nist.gov/cuu/Units/binary.html
52 --
53 Iain Buchanan <iaindb at netspace dot net dot au>
54
55 A woman may very well form a friendship with a man, but for this to endure,
56 it must be assisted by a little physical antipathy.
57 -- Nietzsche
58
59 --
60 gentoo-user@g.o mailing list

Replies

Subject Author
Re: [gentoo-user] 320GB hard drive maxed at ~280GB? Richard Fish <bigfish@××××××××××.org>
Re: [gentoo-user] 320GB hard drive maxed at ~280GB? Iain Buchanan <iaindb@××××××××××××.au>