Every evening I run a script in AIX production box, which executes below command:
rcp prod_bkup.tar prodapp@IP:/data/appl/prod
This will rcp a backup of around 11 GB from production to another machine (runs every evening so overwrites previous one). Just to keep the backup safe. Since 2-3 days,... (0 Replies)
Hi,
I'm pritty new to C, but a recent bug in a program i've been using has forced me to debug it. But I am unable to find a debugger that can act as a layer between the OS and the program to see whats going on..
The problem is that this piece of software makes a connection through localhost... (2 Replies)
Dear everyone...
thanks to this forum I am able to do everyday more and more complex scripts...but now I come up with problem with optimisation..
problem 1 - optimise:
here is my code:
while read number
do
nawk -F "|" -v... (8 Replies)
Hi guys,
Im trying to subtract time in ksh script. i.e. basically im querying a database and i want to get the time 10mins before hand..(from)
in ksh
CurrMin=$(date "+%M")
from=`expr $CurrMin - 10`
to=$CurrMin
however if i run this i say at 2 or 3 mins past the hour, i.e.... (7 Replies)
Hi ,
We have 20 jobs are scheduled.
In that one of our job is taking long time ,it's not completing.
If we are not terminating it's running infinity time actually the job completion time is 5 minutes.
The job is deleting some records from the table and two insert statements and one select... (7 Replies)
Dear experts
I have a 200MG text file in this format:
text \tab number
I try to sort using options -fd and it takes very long! is that normal or I can speed it up in some ways?
I dont want to split the file since this one is already splitted.
I use this command: sort -fd file >... (12 Replies)
Hi,
All the data are kept on Netapp using NFS. some directories are so fast when doing ls but few of them are slow. After doing few times, it becomes fast. Then again after few minutes, it becomes slow again. Can you advise what's going on?
This one directory I am very interested is giving... (3 Replies)
I was wondering if I could get some feedback on my script to grab time from our MDM... I blocked out all of the important stuff. I really appreciate any guidance, since I am long out of practice.
#!/bin/bash
serial=$1
# get last seen value of ipad
lastseen=$(curl -s -X "GET"... (11 Replies)
Discussion started by: andysensible
11 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)