IRON File Systems [PDF] is apaper from the 2005 ACM Symposium on Operating Systems Principles.To quote from the abstract:

Commodity file systems trust disks to either work or fail completely,yet modern disks exhibit more complex failure modes. We suggest a newfail-partial failure model for disks, which incorporates realisticlocalized faults such as latent sector errors and block corruption.We then develop and apply a novel failure-policy fingerprintingframework, to investigate how commodity file systems react to a rangeof more

If you boot a Disksuite-using Solaris 8 machine into single-user modeto do maintenance and do a metastat , you'll discover that all of yourmirrored metadevices are marked as needing to be metasync'd, even ifthey actually are fully consistent.

What seems to be going on is that Disksuite doesn't update thingsfrom the on-disk metadata state database when the kernel bringsup the metadevices themselves in early boot. Instead, it defers thisuntil you explicitly run ' metasync -r ',

I have been trying to spec out a new machine lately, which is remindingme all over again how I hate hardware. This time around, the target ofmy particular hate is AMD CPUs, especially the new AM2 ones, where theperformance picture has become so complicated that you need a largechart to understand it.

Choosing CPUs used to be simple: within a given CPU family, the onlything that changed performance was the clock speed, so you could justbuy the fastest CPU your budget and desires afforded

It's not uncommon to have people harsh on Python and similar languagesas being 'scripting languages', not suitable for serious jobs becausethey're not fast enough or they use too much memory, or the like. I haveto beg to differ, because I have a great counter-example.

We use a SMTP frontend daemon to check connections before we bother tostart a real SMTP conversation. This program does our greylisting, ourDNS blocklist checking, connection count limiting, and a number of otherchecks

Henry Spencer recently wrote some very useful words of advice on backupson a local sysadmin mailing list. They struck me as the sort of thingsthat are useful enough to share more widely, so with Henry's permissionI'm putting his message here. (I thought about running just part of hisemail, but the more I read it, the more I wanted people to see all ofit, so I'm just going to put up the whole thing.)

So, in Henry Spencer's

One of my small peculiarities is that I'm an old-fashioned CRT person.By now this is an unfortunate affliction since it's pretty clear thatLCDs are the future, whether or not I really like them. (If the pricesfor good CRTs haven't already bottomed out and started climbing due todecreased production, it probably won't be long.)

Part of the reason I haven't warmed to LCDs is that they have scary andvisible failure modes, like stuck pixels, that

I'd call these stupid spider tricks , exceptthat these were so visibly committed by web spammers. (In one casethey left me their spam, clearly visible.)

• you cannot take a POST form's form elements, turn them intoquery parameters, and then try to GET the result .
• especially if you remove the existing query parameter on the URLof the form's target.
• you get modest bonus points if you POST your query parameterladen URL instead of GET 'ing it. Not enough bonus

As a followup to yesterday's entry :

One of the reasons that interpreters and other interactive, immersivedevelopment environments improve your productivity may be indirect: bygiving you rapid feedback, they give you the feeling that you're gettingthings done, which in turn improves your motivation and morale.

(And of course this is addition to the direct fun you get from havingshiny flashing things happening right here, right now.)

Of course, this is just a feeling of productivity; it may or may not be

I recently had an insight about why so many sysadmins (and programmers)would rather have a root canal than write documentation for any lengthof time. (While some of these feelings can be blamed on people feelingunskilled, not all of them can. Certainly I can't claim with a straightface to be completely unskilled, and the idea of having to writedocumentation for any length of time still makes me gloomy.)

I think it's because documentation doesn't do anything on its own,leading