Category Archives: Tech Problems

Speeding up percona xtrabackup restores

I started playing around with using xtrabackup (or more specifically innobackupex) to backup MySQL. Most of our tables are now innodb so it didn’t make sense to keep dumping everything out via mysqldump.

I had a clone of our master db server in our virtual environment that I was trying to restore the backup onto, but it was taking hours (using innobackupex –copy-back /backup/). I figured that the IO on my virtual servers was just crap and I’d have to grin and bear it. There doesn’t seem to be much around about restoring using innobackupex, even the command options are limited for restores so I thought –copy-back was the only way.

It seems that if your backup is on the same filesystem as where it’s going to end up then it’s a lot faster to use the –move-back option. This changed my restore time from hours to seconds.

innobackupex –move-back /backup/

VLC Airplay on Airport Express

There is a way to stream music to your airport express from VLC (means you don’t have to install iTunes).

Under preferences > all > stream output enter this in the “Default stream output chain”:

#transcode{acodec=alac,channels=2,samplerate=44100}:raop{host=<ip address of aiport express>,volume=175}

Creating Access ODBC datasource under Windows 7 (64bit)

I had to create an ODBC datasource for an access database on my Windows 7 machine and for some reason the *.mdb driver doesn’t show up in the control panel ODBC administrator.

After much swearing and google-ing I found the solution.

In C:\windows\sysWOW64 there is an executable called odbcad32.exe. You need to run this exe as administrator to gain access to all the ODBC drivers that come with Microsoft Office, etc.

Thanks Microsoft for another fine product!

Windows XP 32bit drivers for Dell Studio XPS 435MT

We just recieved a couple of new computers today, shiny new Dell Studio XPS 435MT boxes. As everyone here still runs XP 32bit I decided to reinstall the new computers with the same OS, so we didn’t run into any compatability problems. The problem is Dell doesn’t support any other operating systems on these computers other than Vista 64bit!

After searching around the internet for a couple of hours I found the drivers needed, they are as follows:

Network (Intel 82567):*%20XP%20Professional&lang=eng

Chipset (Intel X58):*+XP+Professional&lang=eng&strOSs=44&submit=Go!

Graphics (ATI Radeon 4850):

Audio (Realtek HD Audio):

I hope this helps anyone with a similar problem

Disable SSLv2 in Webmin

I’ve been battling with Webmin trying to get SSLv2 turned off so I can comply with Hackersafe/McAfee Secure.

I managed to do it this morning, this is how I did it:

– Upgrade to version 1.430
– Webmin -> Webmin Configuration -> SSL Encryption
– Enter HIGH:-SSLv2:-aNULL into the Allowed SSL Ciphers field (new as of 1.430)
– Restart Webmin

You can check that SSLv2 is disabled by running this from the shell/command line:
openssl s_client -connect localhost:10000 -ssl2

If you get lines like these, SSLv2 is disabled:
419:error:1407F0E5:SSL routines:SSL2_WRITE:ssl handshake failure:s2_pkt.c:428:
420:error:1406D0B8:SSL routines:GET_SERVER_HELLO:no cipher list:s2_clnt.c:450:

SiXXs down?

For some reason seems to be down. I’m unable to connect my IPV6 tunnels to their PoP’s or connect to their website. Does anyone have any idea why they’re offline?

Update: Seems to be back up now. It’s safe to restart your aiccu now

iPhone 3G and Linksys WAG54G v3 incompatibility

For some reason the iPhone 3G will not connect to this wireless router. There has been talk that this is fixed in the latest firmware but as of writing this it is not fixed in the latest AU/NZ firmware (1.00.23).

I found a temporary solution for the problem though. If you limit your router to 802.11B only then the iPhone will connect without a problem. As soon as it’s changed to mixed network or 802.11G only then it will fail to connect.

Update: I’ve found that the AU firmware from the AU linksys site works fine on the NZ WAG54Gv3. I’m using 1.00.46 and the iPhone 3G now connects under 802.11G without a problem.

Monitoring Apache with LARRD and Big Brother

I managed to figure out how to monitor Apache with Big Brother and LARRD. As it’s not very well documented I thought I’d share it with everyone.

First set your apache server to display status in the apache httpd.conf:


SetHandler server-status
Order deny,allow
Deny from all
Allow from

ExtendedStatus On

Setting extended status to On does slow down the server a little bit, but it’s usually not noticeable. Remember to limit access to the status page to just the IP where your Big Brother server is monitoring from.

Add apache to @DATALIST in

Then in your (under the larrd directory) you’ll need to hardcode the servers you want to monitor.

%host_h = (
‘server01’ => {
port => “80”,
url => “”,

The first part of the host_h array is to identify which server to attach the RRD file with. In this instance I’m monitoring a server called server01 and the website I have setup with the server-status page is If your host is a FQDN (fully qualified domain name) then you can omit the full url and just have /server-status?auto and Big Brother will work out the URL.

With any luck you’ll have 4 new graphs on your trends/LARRD page.

MySQL and Redhat Enterprise Linux 4

I ran into some problems with MySQL on RHEL 4 when SELinux was enabled. When starting MySQL it would come up with this:

Starting MySQL...................................[FAILED]

And the following in /var/log/messages:

[code]Dec 1 14:02:52 searchdev kernel: audit(1164934972.432:5): avc: denied { append } for pid=3071 comm=”mysqld” name=”searchdev.err” dev=sda6 ino=1687755 scontext=root:system_r:mysqld_t tcontext=root:object_r:var_lib_t tclass=file[/code]

All fixed though thanks to this page: