Hlynes.com

When I originally set up the ZFS on my development v880 I added the internal disks as a raidz together with two volumes off the external fibre-channel array. As is the way with these things the development box has gradually become a production box. And I now realise that if the server goes pop I can’t just move the fibre-channel to another server because the ZFS pool contains that set of internal scsi disks.

To my horror I now discover that you can’t remove a top-level device (vdev in ZFS parlance) from a pool. Fortunately I have two spare volumes on the array so I can create a new pool and transfer the existing zfs filesystems to it. Here is a quick recipe for transferring zfs filesystems whilst keeping downtime to a minimum.

zfs snapshot oldpool/myfilesystem@snapshot1

zfs send oldpool/myfilesystem@snapshot1 | zfs receive newpool/myfilesystem

this will take a while but the filesystem can stay in use while you are doing it. Once this finishes you need to shut down any services that are relying on the filesystem and unmount it.

zfs unmount oldpool/myfilesystem

And take a new snapshot.

zfs snapshot oldpool/myfilesystem@snapshot2

you can now do an incremental send of the difference between the two snapshots which should be very quick.

zfs send -i oldpool/myfilesystem@snapshot1 \
             oldpool/myfilesystem@snapshot2 | zfs receive newpool/myfilesystem

Now you can point the services at the new filesystem and start over until all the filesystems on the original pool have been transferred.

Filed by huw at 9:32 pm under SysAdmin
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Is about to start..

http://www.lugradio.org/live/2007/index.php/Main_Page

I am feeling a bit fragile today due to excessive beerage. Fortunately I’m not speaking this year so I can find a quiet corner to go collapse in..

Filed by huw at 9:54 am under Uncategorized
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I’ve been running some tests at work on a shiny new Sun x4600 with 8 dual-core Opteron processors.

It’s very nicely put together.

So far benchmarks have ranged between “That’s really quite fast” and “Is it powered by Hamsters?”.

More pics here

Filed by huw at 5:34 pm under SysAdmin, Tech
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I’m supposed to be going on a site-visit to Birmingham University today. Instead I will be in the office because none of the trains I need are running.
Apparently rain is now an adverse weather condition.

edit 26/06/2007
OK given that thousands of people have been evacuated from their homes, maybe it does count as adverse weather.

Filed by huw at 8:34 am under Uncategorized
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Skated the new Severn bridge last night..

Hurt.. So.. Much..

Filed by huw at 8:52 am under Life
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Jamie Cansdale the creater of TestDriven.NET is having some lawyer issues with MicroSoft.
As one commenter says:

“Is it safe for me as a developer without a large legal department to work with Microsoft technology? “

To which the answer, of course, is No.

Filed by huw at 1:33 pm under Tech
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Very cool video from Harvard, taking us on a whistle-stop tour of the inside of a cell. The first version is the condensed version with all the pretty animation and no actual science.

There is also the full 8 minute version where generic-science-guy actually explains what’s going on.

Filed by huw at 8:40 pm under Science
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Most people will no doubt have already seen this delightful interview with Bill Hilf. In this interview Bill, who I had previously taken to be an energetic and eloquant linux engineer working on Windows/Linux integration issues, reveals himself to be not so much the Devil, as the man who goes and gets the Devil a pack of cigarettes. In my more charitable moment I imagine Bill dragged around south-east asia by a brutal MSFT minder, forced to say things he doesn’t really believe: “It spreads the FUD or it gets the hose again.”

“The Free Software movement is dead. Linux doesn’t exist in 2007. Even Linus has got a job today.”

OK Bill, I’m surprised no-one has told you this, but when people say Free software they mean it was released under a Free Software license. It doesn’t mean that the person that wrote it wasn’t paid.

“most customers run a distribution - RedHat, Novell, Suse or Mandriva. Most of the work on maintaining the Linux kernel is done by developers working for these distributions”

Indeed most people don’t build a linux distribution from scratch bootstrapping everything from the compiler on up themselves. In other news: if you stand outside in the rain you’ll get wet. Jonothon Corbet’s recent study for LWN shows that Bill is indeed correct that most kernel code comes from paid developers. But, and I hate to keep banging this drum, that doesn’t mean it isn’t Free Software. This just shows that real companies with real business models can write free software without the world coming to an end. This stands in stark contrast to what some people think.

“Hilf accused his former employers, IBM, of starting a standards war simply because they wanted a part of the Office market. People do not want ODF (Open Document Format), but they want a way to control the information they create, he claimed.”

ODF has been open since Star/OpenOffice was open-sourced in 2000. In order to make it as easy as possible for people to write their own implementation of ODF the time was taken to properly standardise it. This process involved at least IBM and Sun, and happened before OpenXML was even talked about. I can’t even begin to grasp how this could be characterised as a standards war.

There is more in a similar vein, but I’m going to choose to assume that Bill contracted cerebral malaria while he was in Thailand.

Filed by huw at 3:49 am under Tech
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The newest addition to the racks at WeSC is a Dell 3250. Two Itanium processors, redundant power supplies and a proper lights-out management card.

Total Cost?

Less than 500 quid from ebay.

Filed by huw at 6:39 pm under SysAdmin, Tech
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As reported by ZDNET. Apparently a version Solaris that will be more friendly to linux admins. I can’t help but be under-whelmed by this news. Isn’t this what Nexenta are already doing?

In other news my Solaris 10 V880 is apparently not cursed. The problems all stem from a quad-gigabit card that is slowly dieing and spewing noise accross the PCI bus.

Filed by huw at 1:25 pm under Tech
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