Beyond a certain point you can't improve the performance of running gzip thousands of separate times to process tiny strings. This might be some improvement since awk is replaced by pure shell builtins:
Works Astoundingly!!!
Thanks a lot.
close to 50% execution time is reduced.
Hi ,
i'm searching for files over many Aix servers with rsh command using this request :
find /dir1 -name '*.' -exec ls {} \;
and then count them with "wc"
but i would improve this search because it's too long and replace directly find with ls command but "ls *. " doesn't work.
and... (3 Replies)
Hi All,
I am using grep command to find string "abc" in one file .
content of file is
***********
abc = xyz
def= lmn
************
i have given the below mentioned command to redirect the output to tmp file
grep abc file | sort -u | awk '{print #3}' > out_file
Then i am searching... (2 Replies)
hi someone tell me which ways i can improve disk I/O and system process performance.kindly refer some commands so i can do it on my test machine.thanks, Mazhar (2 Replies)
I have a data file of 2 gig
I need to do all these, but its taking hours, any where i can improve performance, thanks a lot
#!/usr/bin/ksh
echo TIMESTAMP="$(date +'_%y-%m-%d.%H-%M-%S')"
function showHelp {
cat << EOF >&2
syntax extreme.sh FILENAME
Specify filename to parse
EOF... (3 Replies)
Hi Friends,
I wrote the below shell script to generate a report on alert messages recieved on a day. But i for processing around 4500 lines (alerts) the script is taking aorund 30 minutes to process.
Please help me to make it faster and improve the performace of the script. i would be very... (10 Replies)
Hi All,
I have written a script as follows which is taking lot of time in executing/searching only 3500 records taken as input from one file in log file of 12 GB Approximately.
Working of script is read the csv file as an input having 2 arguments which are transaction_id,mobile_number and search... (6 Replies)
Hi,
I have around one lakh records. I have used XML for the creation of the data.
I have used these 2 Perl modules.
use XML::DOM;
use XML::LibXML;
The data will loo like this and most it is textual entries.
<eid>19000</eid>
<einfo>This is the ..........</einfo>
......... (3 Replies)
Hi ,
i wrote a script to convert dates to the formate i want .it works fine but the conversion is tkaing lot of time . Can some one help me tweek this script
#!/bin/bash
file=$1
ofile=$2
cp $file $ofile
mydates=$(grep -Po '+/+/+' $ofile) # gets 8/1/13
mydates=$(echo "$mydates" | sort |... (5 Replies)
Hello,
Attached is my very simple C++ code to remove any substrings (DNA sequence) of each other, i.e. any redundant sequence is removed to get unique sequences. Similar to sort | uniq command except there is reverse-complementary for DNA sequence. The program runs well with small dataset, but... (11 Replies)
Discussion started by: yifangt
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)