The site is very slow...

[Karlos]

In the past I've had a bit of a slowdown now and again and it has always turned out to be a DNS issue and nothing to do with the site itself.

[Karlos]

I've been experiencing slowdowns the last 48 hours which for once are nothing to do with my ISPs DNS. It isn't just my local connection either, the old browser proxy has logged timeout errors in the cURL requests that fetch the pages from amiga.org. Whatever it is, it certainly isn't due to trackers since the proxy itself doesn't execute any javascript code.

[Karlos]

Is there any possibility it might be a DOS attack or brute force hack attempt on the server?

It might be interesting to check the firewall logs.

I remember the relentless attacks I used to get on my server not too long ago coming from all sorts of weird and wonderful places.

Well, it's a shared server, so it's possible the box itself is under load even if this site is not the specific target.

[Karlos]

Okay, now it is ridiculously slow

Oddly enough, it's fine again here :-/

[Karlos]

Well, it's a shared server, so it's possible the box itself is under load even if this site is not the specific target.

I checked the load averages during a period where it went slow for me, there was nothing to indicate the box was under undue load.

However, the following mtr report isn't exactly glowing (indicates problems with my ISP's routing rather than the site itself):

Code: [Select]

                                                         Packets               Pings
 Host                                                   Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. 192.168.0.1                                          0.0%    68    0.4   0.4   0.4   0.6   0.0

// snip lossless hops //

 5. ae1-0.loncr4.London.opentransit.net                 41.2%    68  192.0 190.1 111.3 395.6  58.4 <-- WTF?
 6. tengige0-5-5-0.lontr1.London.opentransit.net         0.0%    68   45.6  53.9  44.6 176.8  20.8
    tengige0-10-4-0.lontr1.London.opentransit.net
    tengige0-13-1-0.lontr1.London.opentransit.net
    tengige0-0-1-0.lontr1.London.opentransit.net
    tengige0-2-0-0.lontr1.London.opentransit.net
    tengige0-7-0-0.lontr1.London.opentransit.net
 7. xe-3-1.r01.londen03.uk.bb.gin.ntt.net                2.9%    68   46.5  66.2  44.4 238.6  42.5

// snip lossless hops //

18. nubira.websitewelcome.com                            0.0%    67  160.3 158.2 152.2 185.6   5.7


[Karlos]

In my case, I strongly suspect the problem is down to my ISP. It isn't the first time problems their end has screwed with my access, but it's interesting to note I'm not alone.

[Karlos]

@ Karlos

Been doing a bit of calculating on how to beat your High Score (Number of posts)...

You: Posts Per Day: 7.88
Me: Posts Per Day: 4.86

Pretty sure you'll be the top poster soon enough at that rate. Having said that, I had more than one protracted period in which I barely posted for months on end.

[Karlos]

I know that some users have complained of unusual slowdowns, but it seems that every now and again in the last few days, I get a 500 error page every now and again, which never used to happen.

Anybody else had this issue lately?

[Karlos]

Yes, I flagged this up the other day. From what I can tell, it's a dodgy vBulletin hook. From a developer's point of view, vBulletin makes use of one of the nastiest PHP features ever conceived, namely the dreaded eval() call.

[Karlos]

I think the problem is becoming more frequent too.

(also: theads merged)

[Karlos]

It seems an old bug has resurfaced:

http://www.amiga.org/forums/project.php?issueid=62

[Karlos]

Right, so last night I disabled a vBulletin module that may be responsible for some of the 500 errors.

The thing is, it's tricky to diagnose with precision (since there may be other factors at work), so we'll have to keep an eye on the error log to see if it was the cause or at least a significant factor.

I had one or two since, but nothing like as many as previously. How's everybody else doing?

[Karlos]

I've identified what may be the cause of most of the 500 errors. It's an old bug, originally reported by Piru:

http://www.amiga.org/forums/project.php?issueid=62

This is the fault of a 3rd party module that the site is which uses a vBulletin "hook" (injects some code) that thanks to a lack of sanity checking fails fatally on evaluation, causing the 500 error.

Disabling the module is not an option for now, I've added a quick work-around (injects the required sanity checks into the hook - lol, injecting the injected code...) that should hopefully mitigate the issue until such time that the actual module itself can be updated/fixed.

[Karlos]

Well I haven't seen a single 500 crop up in the error log since then. The site still lags at times though, but that's likely a different issue.

[Karlos]

Karlos has set the sanity injectors 10! Close your eyes!  :lol:

I know, it's very rare that I actually inject sanity into something :lol: