out of space warning?

out of space warning?

[sys.syphus]

I would like to avoid running out of space. is there a way to know
that I am getting close? i'd like to make a script that runs as part
of my bash prompt and lets me know when i am getting close. i know
there are several ways you can run out of space and I'd like to avoid
all of them.

Re: out of space warning?

[Robert White]

On 12/10/2014 02:54 PM, sys.syphus wrote:
> I would like to avoid running out of space. is there a way to know
> that I am getting close? i'd like to make a script that runs as part
> of my bash prompt and lets me know when i am getting close. i know
> there are several ways you can run out of space and I'd like to avoid
> all of them.

Don't do that either. 8-)

(1) you'll grow to hate it.

(2) You know when you are doing things that take a lot of storage. You 
instinct for system fullness is already part of your brain-meat.

(3) The system isn't going to explode if it runs out of disk space. (old 
UNIX systems used to halt with system errors because running out of 
space prevented pipelines from being created, but that's ancient history).

(4) The only _real_ way to run out of space is to be a data hoarder, and 
no script in the world is going to help you if that's the case. Ha Ha....

You don't check your car's gas tank every time you put your foot on the 
brake, you don't want to check your free space every time your system 
finishes every tiny command you type.

Scripts like this are possible in bash, but consider that every "ls" or 
even just enter you type would be followed by a "df" and a "grep" or 
whatever in whatever window you are using at the time. etc.

IF you think you are going to run out of space, and you are using _any_ 
kind of window system, then start a system manager display for a while 
until you get the feel for how not out of space you really are.

Nothing gets ignored faster than a text element that essentially never 
changes, and once you get in the habbit of ignoring the text you won't 
notice when it actually has something to say.

Re: out of space warning?

[Qu Wenruo]

-------- Original Message --------
Subject: Re: out of space warning?
From: Robert White <rwhite@pobox.com>
To: sys.syphus <syssyphus@gmail.com>, <linux-btrfs@vger.kernel.org>
Date: 2014年12月11日 09:29
> On 12/10/2014 02:54 PM, sys.syphus wrote:
>> I would like to avoid running out of space. is there a way to know
>> that I am getting close? i'd like to make a script that runs as part
>> of my bash prompt and lets me know when i am getting close. i know
>> there are several ways you can run out of space and I'd like to avoid
>> all of them.
>
> Don't do that either. 8-)
>
> (1) you'll grow to hate it.
>
> (2) You know when you are doing things that take a lot of storage. You 
> instinct for system fullness is already part of your brain-meat.
>
> (3) The system isn't going to explode if it runs out of disk space. 
> (old UNIX systems used to halt with system errors because running out 
> of space prevented pipelines from being created, but that's ancient 
> history).
>
> (4) The only _real_ way to run out of space is to be a data hoarder, 
> and no script in the world is going to help you if that's the case. Ha 
> Ha....
(5) Possible known/unknown kernel bug may cause strange ENOSPC during 
balance/replace/scrub... :-)
>
> You don't check your car's gas tank every time you put your foot on 
> the brake, you don't want to check your free space every time your 
> system finishes every tiny command you type.
>
> Scripts like this are possible in bash, but consider that every "ls" 
> or even just enter you type would be followed by a "df" and a "grep" 
> or whatever in whatever window you are using at the time. etc.
>
> IF you think you are going to run out of space, and you are using 
> _any_ kind of window system, then start a system manager display for a 
> while until you get the feel for how not out of space you really are.
>
> Nothing gets ignored faster than a text element that essentially never 
> changes, and once you get in the habbit of ignoring the text you won't 
> notice when it actually has something to say.
>
> -- 
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: out of space warning?

[Duncan]

sys.syphus posted on Wed, 10 Dec 2014 16:54:07 -0600 as excerpted:

> I would like to avoid running out of space. is there a way to know that
> I am getting close? i'd like to make a script that runs as part of my
> bash prompt and lets me know when i am getting close. i know there are
> several ways you can run out of space and I'd like to avoid all of them.

With the concerns about your bash prompt registered...

btrfs filesystem show

... is a good choice.

If you have multiple filesystems you can point show at a device/
mountpoint/label/UUID to get the output for just the one.

You'll want to pay particular attention to the individual device lines.  
Of course you can grep/sed/otherwise-process that down to a single line 
if desired.

If btrfs filesystem show says it's close to out of room, run btrfs 
filesystem df for more info.  There's lots of information on the wiki and 
in various threads here about interpreting the information these commands 
output (it takes both commands to get a good picture, but show is good 
for brief summary, provided you know to look at the device lines not the 
overall total line), and what to do when necessary to return some balance 
to the situation.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

Re: out of space warning?

[Erkki Seppala]

Robert White <rwhite@pobox.com> writes:

> You don't check your car's gas tank every time you put your foot on
> the brake, you don't want to check your free space every time your
> system finishes every tiny command you type.

Well, actually my car makes a bling every 10 km once it reaches <=80 km
range, and I don't mind it at all ;-).

As an actual answer, there are monitoring systems that do this, such as
Icinga (fork of Nagios). In fact, I just recently had the same problem -
starting a big download might eat up the space and thus terminate the
download prematurely although I was in position for hours to make up
more space, so I installed Icinga. Haven't yet configured yet, though,
so cannot say if it's going to help me :-).

A practical alternative: one could write a script that outputs only the
amount of free space in a device and add that number to your prompt;
possibly to your RPROMPT as to now take too much space from your command
line. Idea extensible to displaying only space from volumes with space
less than a critical amount etc.

-- 
  _____________________________________________________________________
     / __// /__ ____  __               http://www.modeemi.fi/~flux/\   \
    / /_ / // // /\ \/ /                                            \  /
   /_/  /_/ \___/ /_/\_\@modeemi.fi                                  \/

Re: out of space warning?

[Robert White]

On 12/11/2014 01:01 AM, Erkki Seppala wrote:
> Robert White <rwhite@pobox.com> writes:
>
>> You don't check your car's gas tank every time you put your foot on
>> the brake, you don't want to check your free space every time your
>> system finishes every tiny command you type.
>
> Well, actually my car makes a bling every 10 km once it reaches <=80 km
> range, and I don't mind it at all ;-).
>
> As an actual answer, there are monitoring systems that do this, such as
> Icinga (fork of Nagios). In fact, I just recently had the same problem -
> starting a big download might eat up the space and thus terminate the
> download prematurely although I was in position for hours to make up
> more space, so I installed Icinga. Haven't yet configured yet, though,
> so cannot say if it's going to help me :-).
>
> A practical alternative: one could write a script that outputs only the
> amount of free space in a device and add that number to your prompt;
> possibly to your RPROMPT as to now take too much space from your command
> line. Idea extensible to displaying only space from volumes with space
> less than a critical amount etc.
>

I understood exactly what you wanted to do with the prompt script. They 
were quite the rage some time back. I can give you examples off the top 
of my head...

But there are issues and costs.

Lets say you use:

PS1="\$(df --human --output=avail / | tail -1) $ "

You'll end up seeing

106G $

and eventually it will be meaningless. And if you bury it in amongst the 
other prompt stuff. So if I added that to my distro's default prompt and 
made it track the current directory as I moved around...


PS1="\[\033[01;32m\]\u@\h\[\033[01;34m\] \w PS1="\$(df --human 
--output=avail \$PWD | tail -1) \$\[\033[00m\] "

it will fade into the background noise just as fast and pointlessly as 
the rest of the prompt you usually ignore. But now there's a fork and 
exec to pay.

The difference between the prompt thing and your car is that it only 
goes "ding" when you need to pay attention. So now you are putting a 
whole if then thing into the deal.

And you can do that too by defining the PROMPT_COMMAND="whatever". That 
command can do anything "before issuing the prompt" including making 
arbitrary checks and making the speaker go "bing" if you are running low.

And how many filesystems will you be watching?

And if you want btrfs specific stuff (a la btrfs fi show /) you need to 
be root, and I dearly hope you aren't logging into your box as root for 
regular use purposes.

And so on...

There is an old saying "The more you over-think the plumbing, the easier 
it is to stop up the pipes."

If you suffer a system problem (like running out of available ram) and 
your system is thrashing you just deprived yourself of the shell prompt 
because that df command is going to be thrashing along with the rest of it.

So you are correct, there are _lots_ of monitoring methodologies out 
there. KDE, Gnome, and XFCE all provide monitoring widgets that can keep 
you aprised of the current state and fullness of your system storage. 
And they can ring bells and change colors when it gets to alarming 
thresholds.

But doing it to your _prompt_ will get old real fast if you are dealing 
when it matters.