02-09-2017
thank you all. I really appreciate the thoughtful and detailed responses provided. i'll mull them over.
thanks again.
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hello all!
I'm a recent college grad now working for a contractor.
I've been tasked with writing a program/script that will verify that something was copied correctly.
This is how the system is used -
The user will get a distribution tape (a 4mm tape DDS3). On this tape are a bunch of... (6 Replies)
Discussion started by: kapolani
6 Replies
2. Shell Programming and Scripting
in HPUX: I am copying oracle datafiles from one mountpoint to another
the total size is about 250Gb. I wanted to perform a checksum on the target and make sure the files came overy properly.
Mountpoints:
/s01 to /u01
/s02 to /u02
I tried using "SUM" on these mountpoints but its taking... (1 Reply)
Discussion started by: jigarlakhani
1 Replies
3. SCO
Does anyone know the answer to this?
When I run "sum -r" on a file that I've down loaded from the sco website, the 1st set of numbers differs from the checksum on the download page but the
2nd set matches.
If I try to install the patch, I get errors.
Anyone has an answer? (3 Replies)
Discussion started by: jn5519
3 Replies
4. Solaris
Anyone can tell me the different between "cksum" and "sum" command on Solaris? I read the man pages but still not get it.
And how to display the md5 checksum for a file.
Thanks, (1 Reply)
Discussion started by: redstone
1 Replies
5. Shell Programming and Scripting
I wanted a script that can give the checksum of a particular zipped file.
Can somebody help me in writing a shell script in getting the checksum of a particular tar file. (1 Reply)
Discussion started by: vkca
1 Replies
6. Shell Programming and Scripting
Hi Guys,
Sometimes, I have a problem with transferred files in ftp session. Thats why I want to produce checksum value in my local server and remote server. But I could not find anyway to produce checksum value of transferred files in remote server.
Do you have any idea?
Thanks,
Emre (3 Replies)
Discussion started by: ce_emre21
3 Replies
7. IP Networking
Hello
I am communicating with two devices using my computer over UDP protocol. The application is running fine. When I monitored the UDP traffic using Wireshark software, I found that there were too many Checksum errors.
Please find attached the png file showing this error. I am about to... (0 Replies)
Discussion started by: AustinCann
0 Replies
8. Solaris
Hi Guys,
I have about MD5 checksum so many times but I can't figure out how to use it. Can someone please show me how to perform an MD5 checksum?
Thanks a lot guys. (1 Reply)
Discussion started by: cjashu
1 Replies
9. Shell Programming and Scripting
hi all i want a script to FTP a file and should generate a quality checksum file
means when I FTP a file from one server to another server it should generate a QC file which should contain timestamp,no.of records in that file
Thanks in advance
saikumar (3 Replies)
Discussion started by: hemanthsaikumar
3 Replies
10. UNIX for Beginners Questions & Answers
Hi Folks,
I need a UNIX script which will copy files(Table wise) from source directory to destination directory (Under table directory) and also creates 2 additional files after getting copied to destination directory with extension .pdy and .ldy , . pdy file will be zero byte file should get... (4 Replies)
Discussion started by: Nicks1412
4 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)