Above is the output of 'free -m' from my linux machine. I did some searching on the internet and some of the articles point that linux is memory hungry ( not that it use up memory very fast, but it will use what is available). In my case, what is the free RAM i have? 46M or 518M. I highly do not think that its 46M + 518M.
The used and free Mem adds up to 1010 ( 963 + 46)
I am quite buffled by the -/+ buffers/cache value, the used and free values also adds up to 1010.
so linux is telling me it has used up 963MB of ram and 46MB is still available but on the other hand, it has 491 used in the buffer and 518 in the buffer is free... *confused and curious*
My total physical ram is 1GB. Would appreciate if anyone can explain and 'de-mysterifiy' me.
when /var directory of my machine gets filled up (85%) i removed some old logs. but after cleaning df -k command still shows that /var is still 85% full.
It can detect the actual disk space only after I restart the machine. Is there a way to force df to reflect actual free space without... (1 Reply)
Hi All,
I have a pair of sun ultra 5_10 with SunOS 5.5.1.
Both are almost equally patched and set up with simillar applications.
host# uname -a
SunOS host 5.5.1 Generic_103640-24 sun4u sparc SUNW,Ultra-5_10
Even though both have
same amount of RAM ( 512 Mb ) ,
... (1 Reply)
What's the best way to find out how much memory is being used/available? I tried using free, but I didn't quite understand the output. Can someone explain it?
$ free
total used free shared buffers cached
Mem: 16304536 16256376 48160 0 ... (6 Replies)
I am trying to write a small (and rather simple) script to gather some info about the system and piping it to dzen2
first, i want to explain some things.
I know i could have used conky, but my intention was to expand my knowledge of bash, pipes and redirections inside a script, and to have fun... (14 Replies)
how can I find cpu usage memory usage swap usage and
I want to know CPU usage above X% and contiue Y times and memory usage above X % and contiue Y times
my final destination is monitor process
logical volume usage above X % and number of Logical voluage above
can I not to... (3 Replies)
Hi all,
I'm running a simulator and I'm noticing an slow increase in memory for long simulations such that the simulation has to end because of a lack of memory. A colleague of mine ran Valgrind memcheck and reported that nothing of interest was reported other than known mem leaks. My advisor... (2 Replies)
I recently started working with Linux and wrote my first device driver for a hardware chip controlled by a host CPU running Linux 2.6.x kernel.
1. The user space process makes an IOCTL call with pointer to a user memory buffer.
2. The kernel device driver in the big switch-case of IOCTL,... (1 Reply)
hi , I have a problem about getgroups usage on linux. getgroups can get supplementary groups of a process but if i run a process with root account and I want to get supplementary groups of nobody then what i should do to realize that. (4 Replies)
Hi,
I'm looking into doing a few performance tweaks by adjusting my max memory on a few lpars.
I would to create a time stamp script so i could review it for a week and determine how much space i can lower my max memory to so i could reclaim and allocate that memory to where it is needed the... (2 Replies)
Discussion started by: vpundit
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)