[BALUG-Admin] /var space issues on balug VM, almost certainly from Internet miscreants & their bots
Michael Paoli
Michael.Paoli@cal.berkeley.edu
Sat Apr 24 06:30:52 UTC 2021
/var space issues on balug VM, almost certainly from Internet
miscreants & their bots
So ... bit more background on this below,
and see also wiki page:
https://www.wiki.balug.org/wiki/doku.php?id=system:annoyances
I'll likely have the more detailed analysis/summary/progress
there - including also history of the wiki page.
I'll likely post more to
BALUG-Admin <balug-admin@lists.balug.org>
when it's more-or-less resloved ... or other major or possibly
significant developments/findings/changes.
Anyway, feel free to ask/discuss on BALUG-Admin if you may wish (or toss
about ideas/suggestions/questions/whatever).
Anyway, I thought the list traffic would be more fitting for
BALUG-Admin than BALUG-Talk, so ... pointing that discussion
to here ... also linked (notably on wiki page) to the earlier,
if one wants to catch up on reading that (much or possibly all of which,
might also be captured below).
references/excerpts:
> From: "Michael Paoli" <Michael.Paoli@cal.berkeley.edu>
> Subject: -->BALUG-Admin Re: [BALUG-Talk] Possible solution of
> blankness or editing outline-only on BALUG DokuWiki?
> Date: Fri, 23 Apr 2021 21:40:57 -0700
> I'm going to suggest taking this discussion to the
> BALUG-Admin <BALUG-Admin@lists.balug.org>
> https://lists.balug.org/cgi-bin/mailman/listinfo/balug-admin
> list, as,
> though the matter does involved Linux somewhat generally, it's much
> more specific and relevant to BALUG and the specific inner
> workings thereof. So, expect my next update and further communications
> on the matter to be on the BALUG-Admin list, and I'll likely start
> it off with
> latest update(s) and some background references/links on the matter, at least
> as of late.
>
> Also ...
> dates, lists, number of members:
> YYYY-MM-DD announce talk admin
> 2021-04-01 832 259 35
> https://lists.balug.org/pipermail/balug-admin/2021-April/001046.html
> I'm guestmating probably not around 259 subscribers are that interested
> in these particularly details ... but quite possibly closer to about
> 35 are ... or would be.
> I may well also put up a wiki page regarding findings/developments ...
> or maybe update an older one if such suitable wiki page already exists.
>
> Anyway, I still have some 'work' to do ...
> # date -Iseconds && df -h /var
> 2021-04-24T04:39:59+00:00
> Filesystem Size Used Avail Use% Mounted on
> /dev/mapper/balug-var 6.4G 5.9G 287M 96% /var
> #
>
>> From: "Michael Paoli" <Michael.Paoli@cal.berkeley.edu>
>> Subject: Re: [BALUG-Talk] Possible solution of blankness or editing
>> outline-only on BALUG DokuWiki?
>> Date: Fri, 23 Apr 2021 08:44:22 -0700
>
>> Well, not out of the woods yet.
>>
>> Have done fair bit of compression (even using xz -9) of some
>> moderately older data on /var ... and have grown /var several
>> times, ... yet it filled up again very recently (or exceedingly
>> close - I saw it at 100% again, but that's probably rounded, so
>> at least >99.5%).
>>
>> So, at present, now have:
>> # df -h /var
>> Filesystem Size Used Avail Use% Mounted on
>> /dev/mapper/balug-var 6.4G 5.7G 491M 93% /var
>> #
>> And very recently (only few days back) that was:
>>> df -h /var
>>> Filesystem Size Used Avail Use% Mounted on
>>> /dev/mapper/balug-var 4.9G 4.5G 190M 97% /var
>> Can't just keep growing /var indefinitely.
>> Much of the volume is mail and related - logs, queued mail,
>> bounces & failures, mail to listadmin and postmaster, etc., and mostly
>> lots of other nuisance stuff - fail2ban database takes fair bit of space,
>> but trimming what that holds would increase data in other logs - notably
>> of lots of nuisance failed login/authentication attempts and the like.
>>
>> And, even if I caught it before completely full, some services (e.g.
>> exim4) will proactively stop processing when the free filesystem
>> space runs too low.
>>
>> So, yeah, I'll need to do some more work on it. May need to analyze why
>> it's ballooning more than it was in past - what's the nature of the
>> problematic traffic that keeps driving up the storage.
>>
>> I suspect it's mostly spam (and attempts thereof) and bad bots
>> doing/attempting stuff ... essentially all some type(s) of nefarious
>> unwanted traffic chewing up resources.
>>
>> So, in only a couple days or so, it's already nearly 1.5 GiB more data,
>> and that's already after having done fair bit of aggressive data
>> data compression on some older data (e.g. some of the older mail data
>> easily compressed from around 200 of MiB to under a few tens of MB ...
>> and I even moved the compressed off of the /var filesystem).
>>
>> So, ..., yeah, miscreants on 'da Internet ... more work for me to do. :-/
>>
>> Would also be nice to get some of that /var space back, and not have to give
>> so much of it over to what's basically mostly unintersting crud.
>>
>> And, have had stuff like this happen before, ... e.g. like bad bots trying
>> to register on wiki - and chewing up huge volumes of space ... that's why
>> there's no self-registration option anymore ... blame it on abusers on
>> 'da Internet. Manual registration only now. Even captcha's weren't really
>> enough for most of that ... bad bots still pounded away and repeatedly
>> filled up log space. Maybe more fail2ban config would help that
>> ... but then
>> that also ends up chewing up additional space with its database ...
>>
>> # du -x /var | sort -bnr | head -n 12
>> 5866812 /var
>> 2102592 /var/lib
>> 1249060 /var/log
>> 1017624 /var/spool
>> 1015100 /var/mail
>> 932200 /var/spool/exim4
>> 731780 /var/lib/fail2ban
>> 616584 /var/lib/clamav
>> 531456 /var/log/apache2
>> 505952 /var/log/exim4
>> 491980 /var/spool/exim4/input
>> 364892 /var/spool/exim4/msglog
>> #
>>
>>> From: "aaronco36 via BALUG-Talk" <balug-talk@lists.balug.org>
>>> Subject: Re: [BALUG-Talk] Possible solution of blankness or
>>> editing outline-only on BALUG DokuWiki?
>>> Date: Thu, 22 Apr 2021 16:21:14 +0000 (UTC)
>>
>>> Quoting Michael Paoli <Michael.Paoli at cal.berkeley.edu> from [1]:
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> Thanks for the report, but I'm unable to reproduce the issue.
>>> Anyone else able to reproduce it? Are you/anyone seeing the
>>> issue at this time? Anyone else also see it earlier?
>>>
>>> I've tried the following on:
>>> https://www.wiki.balug.org/wiki/doku.php without being able to
>>> reproduce the issue:
>>> Chromium
>>> Chromium incognito mode
>>> Firefox
>>> Firefox private browsing mode
>>> Lynx
>>> curl
>>> wget
>>> Chome on Android from another ISP
>>> Chrom icognito mode on Android from another ISP
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> Cut-and-pasted a text screen-capture and submitted it as a
>>> [BALUG-Test] 'Test of BALUG Wiki pages' posting yesterday morning;
>>> see [2].
>>> AFAICT, that "blankness or editing outline-only issue" for BALUG
>>> DokuWiki pages [3] and [4] occurred from before 08:00am PDT up
>>> through the late morning, and then went away by mid-afternoon
>>> yesterday.
>>> Probably reloaded both those BALUG DokuWiki pages a half-dozen
>>> times or so over the morning time-period using mostly Firefox-ESR
>>> standard mode and Firefox-ESR private browsing mode, and maybe
>>> once or twice using TOR browser in its [least] Safe mode.
>>>
>>> Same results for all browsers used to test those pair of pages
>>> during that entire morning time-period.
>>>
>>>
>>> Quoting Michael Paoli <Michael.Paoli at cal.berkeley.edu> from [5]:
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> That may have done it.
>>> Looks like I need to add more space to /var and/or clean some more stuff
>>> off of it:
>>> df -h /var
>>> Filesystem Size Used Avail Use% Mounted on
>>> /dev/mapper/balug-var 4.9G 4.5G 190M 97% /var
>>> #
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> Thanks much, Michael, for effectively diagnosing and resolving the
>>> issue! :-)
>>>
>>> Besides considering the issue arising from the DokuWiki site
>>> itself or BALUG's device /dev/mapper/balug-var, was also
>>> considering the possibility that the issue might have arisen from
>>> my own browser client.
>>>
>>> Why so?
>>>
>>> Well, there was no issue whatsoever with successfully loading
>>> BALUG DokuWiki pages [3] and [4] throughout Sunday and Monday of
>>> this week.
>>> What changed on Tuesday afternoon was upgrading Firefox-ESR to a
>>> slightly higher, minor version as per 'less
>>> /var/log/apt/history.log' :
>>>> Start-Date: 2021-04-20 14:10:03
>>>> Commandline: apt upgrade
>>>> Upgrade: firefox-esr:amd64 (78.9.0esr-1~deb10u1, 78.10.0esr-1~deb10u1)
>>>> End-Date: 2021-04-20 14:10:15
>>>
>>> One or more bugs in the upgraded FF 78.10.0esr could have
>>> conceivably rendered text and links in the BALUG DokuWiki
>>> incorrectly afterwards, as remote as this possibility might seem
>>> to be.
>>> It's good to know that this wasn't the case at all, and that this
>>> latest Firefox-ESR browser was fine after all :-)
>>>
>>> Thanks again Michael!
>>>
>>> -Aaron
>>>
>>> ===========================
>>> REFERENCES
>>> ===========================
>>> [1]https://lists.balug.org/pipermail/balug-talk/2021-April/000220.html
>>> [2]https://lists.balug.org/pipermail/balug-test/2021/000048.html
>>> [3]https://www.wiki.balug.org/wiki/doku.php
>>> [4]https://www.wiki.balug.org/wiki/doku.php?id=balug:offered_wanted_hardware_etc
>>> [5]https://lists.balug.org/pipermail/balug-talk/2021-April/000221.html
>>> ===========================
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