Just recently I’ve been experimenting with VMWare Server on a Linux host and although it’s easy enough to use the console to manage it from a Windows PC, I normally only have my aging PowerBook to hand.
Since there’s no proper OSX console application for VMWare (why not!?), I needed to figure out a different way to manage the virtual servers.
Two options immediately spring to mind – (1) Fire up Virtual PC, Start Windows, Use the Windows console, or (2) Find a way to use the Linux VMWare console.
Category: Linux
MySQL bug (followup)
As a followup to my previous MySQL bug post, I tried PostgreSQL and didn’t like it all that much. I found there was too much of a learning curve for someone who’s only really used MySQL to any great extent. It’s probably a better alternative for someone who is used to something like Oracle.
MySQL bug
It seems that in gaining over 100,000 players, Kevan’s Urban Dead game has managed to find a bug in MySQL that causes corruption of indexes. Unfortunately no-one at MySQL AB is able to replicate the bug so it can’t be tracked down and fixed.
More information can be found in the MySQL forum.
iChat AV through Linux NAT
This assumes the following conditions:
* the Linux gateway is forwards all outgoing traffic after rewriting the source address as the external IP (i.e NAT)
* the incoming policy is to drop all packets unless they’re related to an existing connection.
* Both clients are running iChat AV (comes with Mac OSX Tiger)
* Both clients have AIM accounts.
To allow an external user to contact someone on the internal network, simply add the following rules to the Linux gateway.
/sbin/iptables -A INPUT -p udp -m udp –dport 16384:16403 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp –dport 5060 -j ACCEPT
Once this is done, you should be able to make and receive audio and video calls with iChat AV. I’ve not tested it with multiple clients on the internal network talking to multiple clients externally, but it works for one-to-one chats.
I also have the ip_conntrack kernel module loaded, this might make a difference as well.
Fixing software RAID
The primary drive failed in one of my servers – luckily since it was using mirrored drives the system carried on running until I could get PoundHost to replace it.
However, since it was the primary drive when it was replaced the system wouldn’t boot and they had to use a rescue cd. Here’s what was done to fix it…
Strange SSH/rsync issue
Having ordered a new server, I finally got it yesterday. I thought I’d set it up to act as secondary nameserver, backup mysql and general user-data backup but when I started backing up some of the data from the old server (via rsync over ssh) I found that every few minutes the rsync would die with the error:
Corrupted MAC on input.
This error both showed up in the shell running rsync and also in /var/log/secure on the new server as
Sep 11 16:45:11 server sshd[8254]: Disconnecting: Corrupted MAC on input.
hwclock and Dell servers
Whenever the server is rebooted, I’ve noticed that the time goes a bit screwy and jumps forward an hour, having tried a few different settings I found that it wasn’t just this server but others were having the same problem.
Server hiccups
It seems that every few days something goes wrong with the server. Just this morning it died for some unknown reason and I had to get it rebooted. It was still pinging and services such as pop3/ssh/http would connect but then no banners/prompts etc would appear and the service is unresponsive.
Having looked through a number of logfiles, I noticed that just before the crash, there were a lot of failed SSH login attempts from a few different IPs and having seen this before, figured it was about time I did something about them.
urbandead -> server dead
Kevan’s new site http://www.urbandead.com/ was mentioned on Metafilter and as such has managed to bring the server to a crawl for the last couple of nights. Seems Apache running suexec, running perl, running the main script on the site isn’t so helpful.
Server upgrade
Decided to upgrade the server this site runs on to 2GB of RAM today. Kevan (who writes some interesting things) launched a new game at http://www.urbandead.com/ in the last week or so and the server was creaking a little under the weight of all the hits but mainly due to the amount of memory allocated to buffers in MySQL.