As I was just pondering to myself I relized that emergency's do happen and there are times when people need an anwser to their problem ASAP. So what i was thinking why not add a live chat to this board this way people could chat amongst each other in real time. I know this could be done with a... (1 Reply)
I am a student and I love the computer very much ,
especially in programming. However I know little about
programming .
I don't know which I should learn (JAVA and C++).
Would you like to give me a suggestion ?
Thanks! (6 Replies)
Hi,
i am trying to copy files except the latest, my script goes here
#! /bin/bash
# to copy control files to a local DR server
# copy latest files of archive
#modified on 26-03-2009
#
--get today date
dt=` date +"%Y_%m_%d"`
--get yesterdays date
adt=`(date --date='1 day ago'... (1 Reply)
Hi all:
I need your suggestion about how to making this script
Purpose:-
Monitor log for the system
OS: Unix Sun Solaris 10
Hold oracle database 10 g
Life time for the system cycle to 48 hours
the system working as the follow
1- the system is divided into three steps
2-... (0 Replies)
I have the part of script:
if ; then
make_command="make -f $temp_file"
print $make_command;
err_file="${sym_objdir}error.log"
$make_command 2>$err_file; cat $err_file;
] && ] && exit 1;
exit 0
fi
... (5 Replies)
Hello,
I'm working on a Linux 2.6.32-33-server (Ubuntu 4.4.3).
I typed in man -k package and got e.g. apt
I typed in apt --help and got:
The program 'apt' is currently not installed. You can install it by typing:
sudo apt-get install openjdk-6-jdkI don't understand where this... (2 Replies)
I need help with sed and awk scripts to search for Symmetrix ID=000090009902 and then grep its child disk devices associated to the dead paths and display them only, so that those dead devices can be removed.
test01:/#powermt display dev=all
Pseudo name=hdiskpower0
Symmetrix ID=000090009902... (0 Replies)
I am trying to get output for fcs0 fcs1 side by side with "Date" "FCAdapter_Name" "Last Reset" "DMA_Res" "Adapter_Count" "Command_Res" for all the captured output in fcstat.out
Am I missing any thing below, as its just showing same values all the coloums:
#!/usr/bin/ksh
head -30 fcstat.out... (2 Replies)
Using the korn shell in ubuntu or fedora, I need to compare two forms, each from different files and do the following, form-1 is the dominant form and must be compared to form-2, if the value in field1 of form-1 matches exactly the pre-filled in value in field1 of form2 then I display 'already... (2 Replies)
Discussion started by: smth333
2 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)