6 months of GNOME Shell

May 19, 2012 / 0 comments

Back in November I ranted about the migration of Gnome Shell to Debian/Testing. Plenty of other people did the same thing (or have done the same thing about Unity).

I’d just like to say sorry to any of the GNOME people who felt unappreciated; I know you work hard to try and produce a useful user experience out of the box. I ended up doing the dist-upgrade on my work laptop only a week or so after my home machine, and in the process discovered that the nouveau Mesa driver now supports my machine pretty well. It’s taken me a while to get used to it, but my frustrations with the change have diminished and I haven’t felt the need to move to something different. So, a belated thanks for all your hard work.

Going to DebConf 12

May 12, 2012 / 0 comments


Meant to post this a while ago when I booked the tickets, but life has a habit of being busy at present. I’m pleased to say I’m going to DebConf 12 in Managua. In the off-chance someone else might be on some of the same flights as me, here’s what I’ve booked:


2012-07-07 00:15 SFO -> 08:12 CLT US466
2012-07-07 11:40 CLT -> 13:44 MIA US1831
2012-07-07 16:07 MIA -> 16:45 MGA US4925


2012-07-14 21:15 MGA -> 01:50 MIA US4944
2012-07-15 06:15 MIA -> 08:19 CLT US1800
2012-07-15 09:40 CLT -> 12:08 SFO US1485

There were some single stop options but the timings didn’t them any quicker, they weren’t any cheaper, and these times worked better for me anyway.

The future is here again

Apr 24, 2012 / 0 comments

Back in 2004 when Simon and I went full time with Black Cat one of the first things I did was sort out an ADSL offering, including native IPv6. We were one of the first UK ISPs to offer this (possibly the first; I know A&A had been doing tunneled IPv6 for a lot longer, but I’m not sure exactly when they enabled IPv6 on the PPP session. Also Bogons were fairly quick to enable it as well). By the middle of 2004 I was fully IPv6 enabled; my colo box had a native connection, my entire home network (a /64 for the wired, a /64 for the wireless) was configured, BCN had multiple native IPv6 connections to other ISPs (such as peering over LoNAP). By and large it just worked; I remember at one point looking at a traffic graph link from someone in Australia and them indicating surprise that I’d come in over v6. I hadn’t noticed anything different than normal, which is exactly how it should be.

When we sold BCN in 2007 unfortunately one of the casualties was the v6 support. The ISP that took over the ADSL wasn’t setup to be able to continue the v6 support, nor were RapidSwitch, who took over most of the hosting (I note with sadness that RapidSwitch still don’t seem to be offering v6, though they keep saying it’s a work in progress). So I stopped having any v6 for some time, refusing to slum it with a tunnel.

This changed at the start of last year, when I sought out new hosting for the. I ended up selecting Bytemark, partly because I knew of their commitment to v6. I’d chosen Sonic as my US access ISP, again partly because they offered an IPv6 tunnel service (while not as nice as native v6 over the DSL I felt that a tunnel provided by the DSL ISP was acceptable for access). However a combination of not having a machine that was always on at home, and a dynamic IP on my connection, meant that I never got round to configuring anything permanent up.

Recently I got around to buying a little low powered box to be always-on and this week I finally looked at configuring it up as the tunnel endpoint, planning to do some sort of screen scraping of the web interface to automatically update the tunnel broker information for the rare occurrences when my IP changes. The first nice surprise was that Sonic are now doing static IPs for free (previously you could only have a block of 8 for $20/month extra). That makes things a lot easier. So tonight I configured up the little server as the tunnel endpoint, installing radvd and some basic v6 firewalling. As expected my laptop sees the RAs, automatically configures everything up and my ssh sessions start to go over IPv6 instead. Looks like my phone also does the same. I’m not entirely sure what the NAT on the ADSL router is doing and if inbound connections will fail if there’s nothing outbound holding the translation entry active, but I’m sure I can work around that if it turns out to be a problem. I care more about access than hosting anything on the end of my DSL anyway.

This means I’m finally almost back to where I was nearly 8 years ago, just in time for World IPv6 Launch day.

On arranging meetings

Feb 11, 2012 / 0 comments

I’ve been spending a lot more time recently in meetings. Mostly things I should actually be at. And in general if it’s something I think is reasonable I’ll try to be there. In an effort to help with this I actually keep my work calendar up to date. Given that I’m running Linux on my laptop and the corporate standard is Exchange this requires a little bit of effort on my part (the Thunderbird Provider for Microsoft Exchange and Android support for talking to Exchange are helpful with this).

Sometimes it seems like I shouldn’t bother. I spent this week at a conference, and marked my calendar to indicate I was out of the office. I think I had at least 3 meeting requests, all for things that would actually have been appropriate for me to go to. Last week I managed to be booked for 7 hours of meetings from 7am until noon. That included a 30 minute window where I was triple booked.

The thing is, I’m really not that busy in terms of meetings - you can usually find a spot when I’m free on any given day unless I’m actually not in the office. If you bother to check my calendar, that is.

Another problem I have is the times people like to book meetings at. Booking a technical meeting at 9am isn’t going to get me at my best. Equally doing so at 5pm is likely to have me clock watching to make sure I don’t miss my bus and/or train. Also I seem to work with far too many people who don’t eat lunch and book hour long meetings at midday or 1pm.

I understand sometimes that’s the only time you can get everyone into a room together, but at least bloody ask and explain the need rather than just sending out a meeting invite.

Finally, book meetings of a realistic length. There are some people who invite me to things and cause me to add another 30 minutes on the end, because I know it always overruns.

It’s not all bad. I have a VP who always runs a meeting to time, and never seems to call one for spurious reasons. I’ve also worked with a program manager who will organize the meeting so that if you’re only there for one point on the agenda that’ll get dealt with near the beginning so it doesn’t take up more of your time that it needs to. Funnily enough I’m much more likely to go to things both of these people arrange.

Disclaimer: In the unlikely event anyone I work with who invites me to meetings is reading this, I might be talking about you, but everything I mention has been done by more than one person, so I’m not thinking about anyone in particular for each point.

I want you to see my storage automagically

Jan 22, 2012 / 0 comments

For my day job I build storage systems. A lot of what I do at present involves caring a lot about how different OSes deal with things like new LUNs being presented from a SCSI target, or errors along a subset of the available paths to a device.

It will come as no surprise to you to discover that they all suck (for values of all equal to Linux, Solaris, Windows and VMWare). New LUNs are particularly annoying. I’m in the situation that creation and removal of a LUN is exceptionally easy.

Hmmm. Maybe I need to back up here a bit first. SCSI has the concept of a target (think, device, eg hard drive). Each target can present multiple logical units. Each of these is assigned a number - a Logical Unit Number. Most devices (a hard drive, or a CDROM drive) will present a single LUN. A storage array will tend to present multiple LUNs; one for each volume that is exported to the host. At the host level each LUN really just looks like a separate device (for Linux /dev/sda and /dev/sdb may well be separate LUNs on the same array, rather than 2 separate arrays/hard drives, for example. At the block device level you don’t care about the difference usually).

Anyway. For various reasons I end up adding and removing LUNs quite often. And there are ways for the array to indicate that this has happened to the host (the UNIT ATTENTION/REPORT LUNS DATA CHANGED check condition seems to be favoured these days, as a complete Fibre Channel LIP can be disruptive). What I’d like to happen in that case is the host to pick up the check condition and drop and/or add the devices that have changed. Instead everything wants a manual rescan. rescan-scsi-bus tends to be simplest for Linux. Windows wants a manual refresh in Disk Administrator. VMWare a “Rescan HBAs” from vSphere. Solaris a “devfsadm -C” and possibly a “cfgadm -al” first. And all of these can be temperamental about picking up the changes.

We’ve done a lot about hotplug for the desktop user experience, without doing the same level for the server experience. I appreciate that there are situations that you don’t want your server to reconfigure things without being told to, but the current situation can be detrimental (for example Linux multipathing will hold a device open even after it’s disappeared and is returning an “INVALID LUN” response; it would be much better if it could cleanly close that device and wait for it to return). Storage is capable of being much more than just a single block device these days, and it’s a shame that nothing seems to deal fully with that fact.

(Yes, yes, I should write and submit patches, but I appreciate that there’s not always a simple answer, nor necessarily an answer that works for all situations automatically. Plus, y’know, not enough hours in the day and I hope you all appreciate I’ve taken a break from watching BSG to write this.)

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