Experiences from Operating a 3D Region Server in OSGrid – Part 1
As I outline in the last post, OSGrid is an open grid – servers and user are located on different connections to the internet. While this is very common to the internet, it is quite uncommon to the 3D gaming/virtual world communites.
OSGrid is comparable to the real life usage of the internet. There are users with different locations and connection types (http://osgrid.org/forums/viewtopic.php?f=3&t=694). The servers are spread over the world, some clustered (like my rental regions and the rental regions next door are at the same provider) – some even hosted from homes (comparable to a company VPN). What are the differences?
Influences on operating a 3D Internet service based on Opensim
- Skills of service operators
I guess, you know good and bad webhosts. Servers with high and low speed, websites that are up almost all the time – and a website, which is down every 10th visit. Maybe even a forum that loses all the content after a crash. We will see all this in the near 3D future, since many people with low to none server operations skills and knowledge try to make revenue.
- Selecting suitable hardware for a region server
After tests with ~ 15 hosting providers, where I chose different setups, I can say: Memory matters. CPU affects scripts and avatar count. Network affects stability, teleport/border crossing, avatar count and loading times of objects/textures – maybe the highest impact on user experience.
Memory has influence on possible script and item loading and to avatar count. I do not want to point on speed after beginning to swap. Do not think of opensim as a apache. “Memory burst” will not work on VPS systems – only guaranteed memory can be counted. In general, direct access memory (like in Hyper-V, Xen) is faster than VPS. A interesting discussion in view of memory is the “memory leak”, witch I judge to be not bigger than in outlook. There are dead process witch can count up, but I have seen systems with hundreds of “zombies” running for months in former times. The memory leak (if there is a significant one) can be easily handled by a daily restart, it is a good idea to have for doing a backup (closes files and finishes transactions) anyway. There IS a rising memory usage – but opensim does cache objects in the region – so to be sure whether it is a leak, a developer has to be involved in monitoring.
One point I did find but could not drill down: memory usage is changing as avatars come in and out. However if there are less than 200MB of free RAM, systems tend to get instable – block teleports and all sorts of weird things. (tracked with system monitor on Windows and monit on linux).
Operating System & CLR-Framework
I want go into depth here, because this tends to get into a religious kind of discussion. I have no personal preference, besides I prefer an easy to use, comfortable and affordable desktop/laptop.
Finally the systems based in Windows Server 2008, Vista, Server 2003 and XP with the .Net framework 3.5 did make the most points. I did NOT yet test Windows 7, still need to play with my download. J On the Linux side, OpenSuSe 11.1 with no modification did run perfectly stable (32bit and 64bit) and was performing well. Windows vs Linux must be a decision based on the operators administrative knowledge. There are people running linux system with no firewall and maleware protection and discuss content theft in forums. If a company would do, they would have trouble based on a compliance audit (BSI Grundschutz, ISO 27000x – I don´t even think about PCI if it comes to payment systems) and maybe even legal problems (3rd party rights).
Database
For the everlasting discussion on sqlite vs. Mysql I just want to give a short statement. I did read all(!) database related articles from last 2 months in OSGrid forums and run some benchmarks with both databases. Mysql is faster. Mysql needs own resources (memory) to be fast. Mysql has more well known tools. SQLite needs no setup. SQLite is self contained and robust. If you are a starter to opensim or regions should be as portable/easy to handle as possible, sqlite is your friend. If you run multiple regions on a well equipped server and have maybe some Mysql background, use Mysql. I did not test MSSQL, but would think of results comparable to Mysql, at least.
The second part to this article covers the networking perspective – wich is a much bigger issue.
Cheers,
Ralf
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Data collection did include public information requests, testing cloned regions for user experience while monitored, monitoring of CPU/RAM/uptimes, Monitoring of network traffic, comparison of stability/performance based on 32 vs 64bit, different operating systems and different hosting providers.
Article represents personal opinion – trademarks apply – www.ralf-haifisch.biz
