Archive:Hardware and hosting report

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2006 Q3 Report

General report

By Domas Mituzas - August 2006, extract from his report on both hardware & software, originally posted to foundation-l

One of good news is that we can still stay at same class of database servers, which even are getting much cheaper than before. Database server cost per unit went from $15000 in Jun, 2005 to $12500 in October, 2005, to $9070 in March, 2006. We got four of these servers in March and called them... db1, db2, db3 and db4.

For application environment we did a single $100000 purchase, that provided us with 40 high performance servers (with two dual core opteron processors and 4GB of RAM each). This nearly doubled our CPU capacity, and also provided enough of space for revision storage, in-memory caching, etc.

For our current caching layer expansion we ordered 20 high performance servers (8GB memory, four fast disks, $3300 each), which should appear in production in ~one month. We're investigating possibilities of adding more hardware in Amsterdam cluster. We might end up with 10 additional cache servers there too.

We also purchased $40000-worth of Foundry hardware, based on their BigIron RX-8 platform. We will use that as our highly available core routing layer, as well as connectivity for most demanding servers. As well, this will allow flexible networking with upstream providers.

Our next purchase will be image hosting/archival systems, and now there's still ongoing investigation whether to use our previous approach (big cheap server with lots of big cheap disks), or to deploy some storage appliance.

We reallocated some aging servers to search cluster and other auxiliary, and still continue this practice, so that we'd end up with more homogenous application environment.

2005 Q4 Report

General report

By Domas Mituzas - November 2005

These months were yet again amazing in Wikimedia growth history.

Since September request rates doubled, lots of information added, modified and expanded, more users came. To deal with that site had to improve both software and hardware platforms again.

Of course, more hardware was thrown at the problem. In mid-September three new database servers (thistle,ixia,lomaria) were added to the pool, removing ancient type of hardware from the service. With data growth rates 'old' 4GB-RAM boxes could not keep up with operation, except quite limited one. 40 dual-opteron application servers have been deployed, conserving our limited colocation space, as well as providing lots of performance for a buck. One batch of them (20) was deployed just this week. They're equipped with larger drives and more memory, thus allowing to place various unplanned services on them (9 Apache servers are storing old revisions as well), some servers participate in shared memory pool, running memcached.

One of really efficient purchases was 12k$ worth image server 'amane', providing us with storage space and even ability to backup at current loads. It is running now highly efficient and lightweight HTTP server - lighttpd. So far images are served, but growth of Wikimedia Commons will force us to find a really scalable and reliable way to handle lots of media.

Additionally 10 more application servers are ordered together with a new Squid cache server batch. These 10 single-opteron boxes will have 4 small and fast disks and should enable efficient caching of content.

As all this gear was bought for donated money, we really appreciate community help here, thank you!

Yahoo supplied cluster in Seoul, Korea has finally got into action, bringing cached content closer to Asian locations, as well as having master databases and application cluster for Japanese, Thai, Korean and Malaysian Wikipedias.

For internal load balancing Perlbal was replaced by LVS, and we've got a nice flashy donated load balancing device that may be deployed into operation soon as well. LVS has to be handled with care and several tiny misconfiguration incidents seriously affected site performance. Lately the cluster has became quite big and complex and now we need more sophisticated and extensive sanity checks and test cases.

There are lots of work in establishing more failover capabilities - we will be having two active links to our main ISP in Florida. Static HTML dump is (becoming) nice and usable and may help us in case of serious crashes. It can be served from Amsterdam cluster as well!

As for last several days we managed to bring cluster into quite proper working shape, now it's important to fix everything and prepare for more load and more growth and yet another expansion. We hope that we will be able with the help of community to solve all our performance and stability issues and avoid being Lohipedia :)

Lots of various problems were solved so far in order to achieve what we have now, and lots of low hanging fruits have been picked. What is dealt now with is complex and needs manpower and fresh ideas as well.

Discussions are always welcome on #wikimedia-tech in Freenode (except during serious downtimes :) .

And, of course, Thanks Team (or rather, Family)! It is amazing to work together!

Cheers, Domas

Links to last purchases

2005 Q3 Report

General report

By Domas Mituzas - September 2005

Already in March it was clear that we needed more hardware to solve our main performance bottlenecks, but there was lots of hesitation on what to buy. This somewhat ended in mid-April, when we ordered 20 new application server (Apache) boxes, which were deployed in May. Then again, our main performance bottleneck happened to be our database environment, which was resolved by ordering and deploying two shiny new dual-Opteron boxes with 16GB of RAM each, accompanied by an external Just a Bunch of Disks (JBOD) enclosure. In this configuration we eliminated previous bottlenecks, as disk performance and in-memory caches were critical points. These two boxes have already shown to be capable of handling 5000 queries per second each without any sweating and were of great aid during content rebuilds during the MediaWiki 1.5 upgrade (we could run live site without any significant performance issues).

Lots of burden was removed from databases by using some more efficient code, disabling really slow functions and, notably, deployment of the new Lucene search. Lucene can run on cheap Apache boxes instead of our jumbo (well, not that really in enterprise scale) DBs, therefore we could scale up quite a lot since December with the same old, poor boxes. Archives (article history) were also placed on cheap Apache boxes thus freeing expensive space on the database servers. Image server overloads were temporarily resolved by distributing content to several servers, but a more modern content storage system is surely required and planned.

There were several downtimes related to Colocation facility power and network issues, of which the longest one was during our move (on wheels!) to a new facility, where we have more light, power, space and fresh air. Anyway, acute withdrawals were cured by working Wikis.

There was some impressive development outside Florida as well. A new datacenter in Amsterdam, generously supplied by Kennisnet, provided us with a capability to cache content for whole Europe and neighboring regions. Moreover, it enabled us to build distributed DNS infrastructure, and preparations are made to serve static content from there in case of emergencies. Various other distribution schemes are researched as well.

Currently there are preparations made to deploy our content in a Korea datacenter provided by Yahoo. There we sure will use our established caching technology, but we might already take one step further and put our master content servers for regional languages there. As well, further expansion of our existing Florida content-processing facility is thought about.

Multilingual error messages finally implemented !

On the 28 of September, Mark Ryan announced that multilingual messages had now been implemented on the Wikimedia squids. Here is an incomplete list of those in IRC who helped with translations: taw, Mackowaty, WarX, SuiSui, aoineko, Submarine, Rama, Frieda, Quistnix, galwaygirl, Fenix, mnemo and avatar. Particular thanks must go to fuddlemark for extensive Javascript help, and to Jeronim for implementing the new message across the squids. Everyone's help has been greatly appreciated. :)

Now, we just hope not to see these messages too often...

2005 Q2 Report

Wikimedia servers gets a new facility

On June 7, 2005 (UTC), Wikimedia cluster was moved to another facility, as there would be more space. The newer facility is better designed and in the same city of former one, in Tampa, Florida. Moving had to be done all at once, with all network and servers turned off and moved across the street. It took nearly 11 hours from 07:00 UTC, 03:00 at the local time. Domas Mituzas

New appointements on the Foundation team

On the 25th of June, Jimbo Wales has announced the appointement of the following people on official positions within the Foundation organigram. In particular
- Chief Technical Officer (servers and development): Brooke Vibber
- Hardware Officer: Domas Mituzas
As Jimmy Wales best put it, the board encourages these people to work closely with, and even helps to formulate committees within Wikimedia. These appointed positions do not have any special power within any of those groups, but serve as a point of contact to the Board, and to the community, to ensure that information is flowing between all concerned parties within their own fields of xpertise. The appointment is a reflection of the work these people are already doing in these areas, and should not be seen as a disincentive to others to become involved.

Links

http://wikitech.wikimedia.org/view/Server_admin_log
m:servers : updated list of our servers
m:Developer : list of developers involved in software and hardware management.
LiveJournal: a way to communicate about servers issues with the community. That's one more feed for your preferred RSS aggregator.