Listen, if you know a bit of programming in C and need to program unix-type operating systems the next transitive stage is for sure C++. However, have in mind that Java is like learning C but 99% object-oriented(o.o.) and with no pointers or memory-management tricks. It would be good for you to see... (5 Replies)
I know that the rules say no school questions but I am in advanced topics and am going to go to college for programming and I want to find a easy first OS to start me out, please help, thanks (3 Replies)
There are soo many flavors of linux and i just cant choose/find the right linux for me...
I am hopeing for a linux that is a
Workhorse
Can fit of a seires (or 1) disk(s)
Lots of features (admin/mod features)
A learning mode or a detailed tutorial
Can work side by side with windows... (12 Replies)
I would like to choose an OS which is both very secure and very stable.
Which one of these 2 would be the best option: FreeBSD or Solaris 10 ?
I plan to use this OS as a very basic desktop pc using: a word processing program, emule/amule/p2p and an email client such as evolution. (1 Reply)
Hi all
Help me find the best distro for the following configurations:
Intel pentium IV 1.6 Ghz
128 MB RAM :(
40 GB Hardisk with one very big partition more than 35 gb n another 2 gb partition.
windows xp is already installed but has enough free space (26gb).
Which linux will be... (0 Replies)
Dear Friends,
If I use Slackware for learning whether it will make any confusion in administering/using Redhat and SuSE since I have checked slackware is more like BSD.
Thank you. (4 Replies)
Hello Friends,
I am trying to troubleshoot one scenario for the customer. In their server configuration, each vhost has it's own user. The option is to shell access chrooted.
The question is where would be the best place to store the authorized_keys file so that we can ssh in from the... (0 Replies)
Hi,
I just ordered an Skylake NUC and will run Linux on it.
My distro of choice has been Ubuntu but I am fed up with the release cycle and would like more of a rolling release. I would say I am an intermediate level Linux user.
It's going to be a HTPC, I want to have the latest kernels... (0 Replies)
Discussion started by: rthorntn
0 Replies
LEARN ABOUT DEBIAN
bup-margin
bup-margin(1) General Commands Manual bup-margin(1)NAME
bup-margin - figure out your deduplication safety margin
SYNOPSIS
bup margin [options...]
DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two
entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids.
For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit
hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by
its first 46 bits.
The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits,
that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits
with far fewer objects.
If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if
you're getting dangerously close to 160 bits.
OPTIONS --predict
Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer
from the guess. This is potentially useful for tuning an interpolation search algorithm.
--ignore-midx
don't use .midx files, use only .idx files. This is only really useful when used with --predict.
EXAMPLE
$ bup margin
Reading indexes: 100.00% (1612581/1612581), done.
40
40 matching prefix bits
1.94 bits per doubling
120 bits (61.86 doublings) remaining
4.19338e+18 times larger is possible
Everyone on earth could have 625878182 data sets
like yours, all in one repository, and we would
expect 1 object collision.
$ bup margin --predict
PackIdxList: using 1 index.
Reading indexes: 100.00% (1612581/1612581), done.
915 of 1612581 (0.057%)
SEE ALSO bup-midx(1), bup-save(1)BUP
Part of the bup(1) suite.
AUTHORS
Avery Pennarun <apenwarr@gmail.com>.
Bup unknown-bup-margin(1)