by R.I. Pienaar | Oct 30, 2007 | Front Page
Linux virtual hosting is all the rage today and there are literally thousands of companies doing it. One of the old hands in this market is Linode.com. They offer the usual type of thing really, bunch of operating systems to choose from, remote shell to manage it and the VM is essentially yours to do as you please.
Where they really shine though is in their admin tool, it allows you to profile your machine and allocate your alloted storage in many ways, you could for example have 1 linode with 20GB drive space but only use 5GB for one machine running Debian. The rest of the space can be used with OS images for RedHat or something else and you can freely choose to boot any of these as long as you only have one going at a time. I’ve not tried but you could no doubt also share 1 swap partition amongst a lot of OS images, or one /home partition so your development environment travels with you between the various operating systems.
That is really great for software developers who need to test their apps on many distributions. I’ve had machines at them since around 2003 now and have not once had cause to open a support ticket with them. I obviously had outages, the host machines need upgrading some times too and they post work notices on their forums etc about this.
The big thing though is that they don’t just leave you stuck with what you had years ago, they constantly upgrade you as they get more capacity. My machine there started off with 128MB RAM and 3GB drive space it has since without any involvement by me transformed into a 300MB RAM and 10GB storage allocation machine. Obviously my OS image did not grow, I just have some spare storage to allocate to VMs now. Really helpful when I want to rebuild the machine for instance to a newer version of the OS. My bills for these upgrades? Zero, no increase in rate and no setup charges.
If you’re in the VM market and looking for a machine in America, you just have to look at Linode.
by R.I. Pienaar | Oct 29, 2007 | Uncategorized
Some of the UI decisions that Apple made with Leopard is questionable to say the least. The ones that gets to me are:
- The menu bar is semi transparent, thats just lame as your background wallpaper makes the menu harder to read. An annoying fix is to add just the right amount of black or white pixels in a strip at the top of your wall paper. This does not solve the problem if like me you move between laptop monitor and external display being primary depending on your location.
- The glassy dock takes a lot of space and just distracts, all the reflections and stuff makes the very faint dots even harder to spot. A working fix can be found here. See below for a screenshot of my fixed dock.
- The starry desktop background that came out of the box looks unprofessional and badly done, its also too busy and distracting. A very easy fix here.
On the software front, OpenVPN were having some issues, Tunnelblick already has a fixed version out. Site is currently down though.
by R.I. Pienaar | Oct 27, 2007 | Uncategorized
Last night I joined a few 100 people in queuing for Leopard. My first plan was to go to Regent Street but I decided it might be a bit mad out there so I headed to Buewater shopping centre instead.
I am really glad I went there, there were several 100 people in the queue but I got in around 5:15 and were maybe number 15 in the queue so I was in and out in about 10 minutes with Leopard and a swanky tshirt.
I put it on my iMac with no problems at all, re-indexing the spotlight indexes took ages and made my machine a bit slow but once that was done it is all smooth sailing.
So far I have 2 3rd party application problems:
- Parallels let you mount your guest drive as a drive on your mac, for some or other reason this gives a time-out problem. Parallels have committed to a free patch for any issues so Kudos to them
-
Little Snitch stopped working well and will require a paid upgrade to version 2. Version 2 is much improved and I think this is a must-have app so will be happy to pay for it, its very inexpensive.
Other than these problems, I’ve been 100% happy with it. So far I don’t think its a total killer upgrade really, the unified look and feel is nice and makes for an all round more polished feel to OS X something that Microsoft have right for years now with their Designed For plans that requires you to comply to their design guides, I think the unified look and feel of Windows apps is invaluable.
The big feature for me is perhaps the new Finder, quick look and coverflow makes dealing with images so much easier, in the past I had to rely on all sorts of 3rd party apps to just browse images without pain, now Finder does it perfectly.
The biggest disappointment is Spaces. I had high hopes for it, from a UI perspective its too hard to pin applications to a given Space. I might have to stick to You Control: desktops. Will give spaces another try though.
by R.I. Pienaar | Oct 18, 2007 | Front Page
I’ve a machine at Hetzner DE and have been pretty happy with it and their service in general. I used to run VMWare Server on it for virtualisation but have become a bit annoyed at the totally unfixable clock problems that seems to be the norm with VMWare guests.
First the good news. I decided to give XEN a try on it, same setup same spec virtual machine on the host doing the same workload as before, below a CPU usage graph before and after, enough said.
I know it’s not the same technology etc, but XEN VMs will do what I need now so it seems a good option for me.
Now for the bad, I had a few problems:
- Hetzner uses a DHCP/TFTP rescue system that is very useful, if I make a mistake in a network config for example I can sort it out via this. XEN by default works in a bridged mode that will change the MAC address for your eth0 to FE:FF:FF:FF:FF:FF. The problem is that Hetzner uses Realtek NICs which as most people know are uber crap. When the machine gets a normal alt-ctrl-del or other reboot other than a power cycle the NIC does not reset to the original MAC. So if I get a crash I wont ever get to the rescue system. This cost me 119 Euro this weekend in support fees.
- In the past I had a few crashes on this machine, adding acpi=force irqpoll noapic to the kernel command line solved it, however the XEN kernel won’t poll my drives properly without removing the noapic bit, so I hope my machine doesn’t become unstable all of a sudden.
I am using CentOS 5.0 on this machine that came with XEN out of the box so installation was dead easy, creating new VM’s are easy etc and very importantly I can manage the VM’s all through text consoles which was a pain for me under VMWare as I don’t use Windows or Linux, getting console access was tough.
So about the MAC address, this turned out incredibly easy to fix by turning the machine into a routed network setup instead of a bridge, so previously the network was bridging eth0 with the vif’s from the virtual machines onto the wire, this required the MAC address of eth0 to change. Moving to a routed setup required the following changes:
/etc/sysctl.conf:
net.ipv4.ip_forward = 1
net.ipv4.conf.all.proxy_arp = 1
This basically enables routing and sets up proxy arp across all interfaces, this is to work with Hetzner’s routing where they don’t actually add a route to my subnet over my eth0 but over to the switch is connected too. Proxy ARP sorts this out.
/etc/xen/xend-config.sxp:
#(network-script network-bridge)
#(vif-script vif-bridge)
(vif-script vif-route)
(network-script network-route)
This points XEN to its provided route scripts rather than the bridge ones.
Reboot virtual machines and thats that. Machine is perfectly happy, routing traffic and MAC address is correct.
Bonus is now all traffic gets routed through my Dom0 and I can now do all the firewalling there outside of my DomU’s which enhances security as it is essentially a border firewall.
by R.I. Pienaar | Oct 16, 2007 | Front Page
Today I attended the MySQL European Customer Conference in London. I was quite excited about it hoping for some good tech sessions and such, especially after seeing the lineup:
- MySQL roadmap
- MySQL performance tuning including real world examples
- MySQL for online applications
- MySQL for data warehousing and bi
- Presentation by the Swedish Police
- Presentation by Net-A-Porter DBA
- High Availability Strategies for MySQL
- Multiplay Telecom Service Architectures with MySQL Cluster Carrier Grade
- Defining an Effective Storage Engine Strategy
Thats a pretty decent line-up, seemed like a lot of solid tech info in there. I chose to attend the MySQL Roadmap, MySQL for online applications, Net-A-Porter, Multiplay Telecom Service Architectures with MySQL Cluster Carrier Grade and Defining an Effective Storage Engine Strategy
The sessions by MySQL employees were good, obviously done by senior sales type guys but all knowledgeable. The sessions were though aimed at tech management types rather than pure tech people, they contained a lot of what can only really be described as sales talk. This held true for the Datawarehousing, Storage Engine and obviously the roadmap talks.
The session on MySQL for online applications could have just been left out really, nothing was really said of any substance, the basic building blocks of a web architecture was mentioned but just not in any sufficient detail.
I found the data warehousing session good as I am currently running into some needs for this kind of application, the roadmap was very helpful if only to show me that some of the much needed improvements is way down the line ๐
I attended the Pret-A-Porter talk as I was hoping to get some insight into the workings of a big MySQL shop. Turns out the DBA who was running the chat was new in the job and can’t really comment on any of the decisions that got them where they are today. He came up with such gems as ‘to me Hibernate is just this horrible little thing the developers use’ and couldn’t really describe why he made some choices like use InnoDB for everything. When asked how he optimised the database he just said he followed the basic recommendation the MySQL Enterprise Monitor suggested, couldn’t really go into any details. In fact he didn’t even know what hardware they run on.
Further I question the choice of partner for this specific presentation, these guys have about 2GB of data and it all fits into the query caches, they have one database server and is considering moving to a DRDB HA cluster, again he can’t really say why thats just what he was told to do. Frankly, running a MySQL server with 2GB data that performs well is no challenge and few people in the industry that actually use MySQL can learn from this presentation.
I chose the Telecoms Strategies talk as it was touching on MySQL Cluster which is something I have read about but never had opportunity to use. The presentation was well rounded, delivered professionally and gave me a lot of insight in the underlying NDB storage engine that enabled MySQL Cluster. The guys focus on talking direct to the NDB using the API rather than SQL so not quite typical but it was really interesting to get a view on the structure of the engine and how it sticks together. It made it crystal clear to me that Cluster would be a engine you would only use in very specific work loads. This was confirmed later on in the conf.
Overall, I feel I didn’t get value for my buck from the conference. Very little that was said had any bearing on my database that is approaching 100GB with 5000 queries per second.
A co-worker attended the performance sessions, he left equally unimpressed. The guys from MySQL Performancing Blog were constantly having to correct the speaker on his points.
So, again, pretty unimpressed. I think I’d need to attend one of the User Conferences which should have a more tech focus at least in parts ๐
