Archive for September, 2005

Xen networking tip

A useful comment about a networking issue with Xen. Something I’ll have to try out at some point.

On a separate but still networking issue, I noticed that my XenU’s outbound traffic is sporadic (between 800KB/sec and 2MB/sec). The problem is the default qdisc being inadequate. So I fix it with:

XenU# tc qdisc add dev eth0 root tbf rate 50mbit latency 20ms burst 50k

TBF requires kernel option CONFIG_NET_SCH_TBF, but other qdisc should work too if the buffer is large enough to handle the bandwidth. To make this permanent, add it as a ‘up’ line to iface eth0 in XenU’s /etc/network/interfaces.

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Opteron vs. Xeon

A simple Opteron vs. Xeon
benchmark using slamd comparing a dual core Sun v20z and an IBM x345.

Result: Opteron server is 1.6x faster then Xeon server. Turning additional cores on and Opteron server is 2.62x faster then Xeon server.

My new v20z is sitting at the warehouse today. I’ll probably have to find my ear plugs while I’m building it up, but I’m looking forward to seeing how well the Opteron is going to perform.

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Firefox Memory Leaks

Running my persistent desktops via NX I’ve noticed that my long run (week+) Firefox processes often get into memory trouble. It seems this is not the fault of Mozilla. Check the link for a couple fixes.

So if you’ve used Firefox you’ve probably noticed that it suffers from what can be described as a fairly harsh “memory leak”. The main cause of the problem appears to lie within the plugin for Flash content. There are 2 workarounds that I’ve located.

With a little bit of google here is some extra detail on this.

Firefox Tweak Guide [Page 8] Advanced Tweaking:

browser.cache.memory.capacity [Integer] (32768) – This setting determines whether Firefox uses system RAM to cache itself, improving performance. A value of 0 turns off caching into RAM (not recommended), while a value of -1 tells Firefox to automatically determine the amount of RAM to use. I suggest you manually specify the amount of RAM to be used (in bytes) to prevent Firefox from blowing out too much. For example, I recommend a value of 32768 (32MB) for systems with 512MB of RAM or more. For those with less RAM, try a value of 16384 (16MB). If you have any problems, set this value to -1.

Hacking Firefox: Speed Up Your Browser: Installed Memory vs Memory Cache Allocations suggestions.

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Where I’ve been

Joining the meme, here is my travel map.

You can create your own here.

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New data center location

I’ve just moved into a new center, combined with this change I’ve fixed a Xen configuration [1] bug that has been plaguing this site with timeout errors. The addition of SunFire V20z at the end of the month should also improve performance, and also allow me to take my Xen/NX desktop testing to the next level.

[1] vif configuration error where 00:01:00:101 and 00:01:00:01 resolve to the same 00:01:00:01 MAC. The former should be 00:01:01:01.

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What a mess

An account by a survivor of New Orleans.

The thing that amazes me is people taking TVs when there is nothing to plug them into. I can understand the need for food, water and even clothing. But TVs!?!

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Opteron performance

This article “No More Apple Mysteries, Part Two” at Anandtech is a second focus on the PowerPC. Of greater interest to me was the numbers between the Intel and AMD processors.

At the moment I’ve been reviewing the purchase of a new 1U machine and trying to decide between a Sun Fire v20z or a Intel SR1400 Server Chasis. Basically the using an Opteron 248 2.2 GHz or a Xeon Irwindale 3.2 GHz 2 MB L2 800 MHz FSB.

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Beagle review

Short review of Beagle. Of primary interest is the Firefox history indexing. Very interesting. When I get a moment, I’ll upgrade to breezy and get this installed.

Beagle can index a wide assortment of files including documents, MS Word documents, AbiWord documents, Music Files (meta data), Images (meta data), man pages, virtually any text file (including source files, Docbook, rtf and HTML), PDF, Gaim logs, Evolution mail and address books, the Tomboy note system, and several RSS aggregatiors. … A plug in for Firefox indexes web pages as they are viewed, creating a massive web history index (can prove very handy).

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