I had just updated - reinstalled - my RH9 to a Fedore Core 3.
I did not know about the Logical volumes that automatically combined partitions on drive 1 and 2 into one mounted volume. In my attempts to do something with the hdb2 partition - not knowing that it was already in use - I killed my... (2 Replies)
frnds..
can i perform an OR operation in sed syntax ?
if yes.. how?
I need to search for some 2-3 mail addresses in multiple files and delete all those... and instead of them.. I need to insert a new mail id...( these are also other emails in that list .. which sud not be affected )
is... (8 Replies)
Hello. I have a test server that I'm messing around with, and just recently received an error on startup that a logical volume in the root volume group couldn't be re-synchronized. Server boots fine, as the root vg is mirrored, but I'd like to get rid of the error. Here are the details:
... (1 Reply)
Hi can someone please help me on this.
I need to perform this code:
Grep any lines that meets the following criteria
(A AND B) OR (A AND C)
I tried this code, but it didn't work
Grep-I "A &&B" | "A&&C" *.* $
thanks in advance (12 Replies)
Hi,
I have a script testor.s which takes a string as command line argument,
Contents of the script:
#!/bin/ksh -x
if ]
then
echo "error"
else
echo "correct"
fi
Here, though i provide the command line argument as "WO_STMT_05292009", it displays error
Is there... (3 Replies)
I have this script to uvscan-update. Seems like that i am getting logical error at the end of the script. It is updating the script and also giving the error message to update it manually. I have deleted the DAT files to see if it will create new and it does. Below is the error and the script: ... (1 Reply)
I'm trying to find out how many logical partitions our AIX box has. I'm running the command: topas -C
and nothing is showing up. Is it safe to say that there is only one LPAR, which is what AIX is installed on?
Move to AIX - jim mc (2 Replies)
Discussion started by: NycUnxer
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)