Mum’s Second Op (by sarah)

Mum's second partial mastektamy in the other breast went much better than expected. They used a different tequnic but worringly to me they also did not take any lymph nodes this time. They say they don't need to but then they origonally told her she didn't have cancer when the origonal scan shows both lumps in both breasts and from that they told her she was in the clear.

If they had looked properlly later on they could have just done one operation on her a year ago for both lumps and delt with it all. Instead its two lots of operations and depending on the results of the biopsy from the lump they've removed it may be another third operation to remove the lymph nodes to see how its spreading and then more radiotherapy.

But she is in hoping its all ok as are we and she has been knitting like a demon!

It Gets Worse (by sarah)

Here is a news article about Alex that I recieved after having posted earlier

http://www.dailymail.co.uk/news/article-1053151/Six-dead-flood-chaos-thousands-evacuated-homes--weather-set-WORSE.html

I am feeling so sick right now with this.

edit: another news article

http://news.bbc.co.uk/1/hi/england/gloucestershire/7603417.stm

Another Friend Gone (by sarah)

With the taste of one friends memorial still in my mouth from Tuesday I came home last night to find a message that another much younger friend had been killed in an accident at work.

Alaric had already left for London when I saw the message and I hadn't yet unpacked things from the weekend so I couldn't initially find my phone. I didn't and to a certain extent still don't beleive it. I became single minded in one thing - I had to phone Al I couldn't grip on to any other thing in reality.

I found the charger but then couldn't find the phone and then found the phone but couldn't find what I'd done with the charger - I was panicking as if I could change things.

I phoned Alaric and just got the answere phone so I just kept phoning I couldn't think of what else to do. I started doing random things to try and proove to myself that it was some horrible practicle joke - but deep down I knew it wouldn't be - this was the same reaction I had two years ago over Wilson's death but with out the anger.

I looked up his work website thinking that would help - he works up at Birdlip - basically in walking distance. I don't even know why I am writing this becuase it would just embarrasse him if he read it. Alex was at uni with me in my first first year and we had done stuff like caving. He also helped out alot when we where flooded and would meet me in Cheltenham for drinks.

We hadn't met up recently as things had been hectic and we just werent being free at the same time - we where going to do something probably a meal and I was looking forward to meeting his girlfriend that I had heared so much about.

I got through to Alaric and all I could say was please come back - I said I;d got an email saying Alex had been killed. Al said, 'Oh god I'm coming back' he hadnt been able to understand anything else I'd said.

The thing is mums going in for her second partial mastectamy today and normally I would be in getting texts from him asking how it was going but thats not going to happen now and stupid as it sounds I feel like everyone is dying on me.

Alex was so nice and helpful he was even going to lend me some stuff from his scout group for mine. I just can't face that this might possibly be true and at the same time I keep crying.

Filling the lake (by alaric)

With all the rain recently, the place where I park the van has developed an annoying tendency to be a lake. So I have to paddle to get in and out of the van, and so does Sarah - Jean, being sensible, just refuses and asks to be carried.

So I invoked the power of Freecycle and obtained a van full of hardcore, then used a pickaxe to dig out the mixture of hard-packed gravel and mud that comprises the parking area, making a trench which I filled back with hardcore.

After packing it down with a lot of treading, thumping, and the use of the big concrete roller, I dumped the gravel/mud mixture back in, to pack back together again and provide a smoothish surface.

I only had enough to do that one strip, but it's a start! When I've stopped aching from all this work, I'll bid for another load of hardcore on Freecycle and do the side where I get out - then another load for the strip down the middle...

UPDATE

It soon started to rain heavily later that day, so I took another picture. Sure enough, the lake is now constrained to one side of the parking area, and the bit I built up is kept out of the standing water. Yay!

Managing lots of servers (by alaric)

The way OSes work was rather designed around the notion of large centralised systems, which is increasingly out of date. There's too much per-node configuration splattered around all over the place; you have to manually set up processes to deal with it all, otherwise you start to lose the ability to replace machines since their configuration contains mysteries that you may or may not be able to recreate if you rebuild the OS install. You really need to be able to regenerate any machine from scratch in as little time as possible - not just restoring from a backup; you might need to recreate the function of a machine on new hardware, since you can't always get replacements for old setups.

Now, if you can get away with it, you can build your application to support distributed operation - then just set up a sea of identical OS installs by using a configuration script that sets up a server and runs an instance of your distributed app, but a lot of off-the-shelf software sadly fails to support that kind of operation. If you want to run standard apps that use filesystems and SQL databases to store their data, you need to be cunning.

How can we do better? Here's a few (rather brief) notes on an approach I'm experimenting with.

Boot your OS from a CD

Not quite a liveCD, though, since we do want to actually use the local disk for stuff.

• modified RC chain that (union?) mounts /etc from the hard disk and then runs with that to get local network etc. configuration.
• swap, /tmp, /var etc on the hard disk, obviously.
• Makes rolling out new versions of the OS easy; forces you to prototype the system on a hard disk on a staging server or VM, then when it's ready, burn a CD, test the CD in a staging server, then if it works, burn a hundred copies and roll them out. USB sticks are another option, but a little more awkward in datacentre environments. Cost of having a human go and re-CD every server exists but is low and provides safety compared to automatic rollouts that could go disastrously wrong. The fact you can roll back by putting the old CD back, having a truly read-only root filesystem and OS (making it harder to hide rootkits) is great, though!

Use Xen

• The actual loaded OS is just a Xen dom0 setup
• Prebuilt domU root images exist on the CD-ROM, which are then spun up (based on settings in /etc on the hard disk). The root images get given a partition from the hard disk which contains their /etc and swap, and any local storage they need, in much the same way as dom0 boots directly from the CD.
• Or your read-only domU root images could be stored on the hard disks of the servers and rolled out via the network; the advantages of distributing them on CD-ROM are a lot smaller than for the dom0 OS, as dom0 can enforce the read-only nature of the domU images, provide remote access to roll back to an earlier version and try again if an upgrade turns out to be bad, etc.

Virtualise storage

• Use local storage on servers just for cached stuff and temporary storage. Eg, we have each server's configuration stored on local disk so it can boot, but that's just checked out from subversion. We put swap on local disks. But the contents of any server's disks should be recreatable by checking the configuration out from SVN again and/or rsyncing any shared mainly-read-only data (domU images etc) from authoritative copies.
• For actual data that we care about, use network protocols (iSCSI, NFS, SQL, etc) to talk to special reliable storage services.
• For domUs that have a criticial local filesystem, we use iSCSI. However, we use software RAID to mirror (or parity-protect) the filesystem over more than one physical iSCSI server, so that either can fail without losing data or causing downtime. Since the domU itself then stores nothing, should it fail (or the physical server hosting it fail), an exact duplicate can be brought up on another physical server and it will connect to the same iSCSI servers to provide access to the same data (and we hope that the filesystem used can recover from any corruption that arose during the failure, or else we're toast anyway).
• Higher level storage protocols (NFS, SQL, etc) are served out from domUs that, as above, have stable block-level storage from software-RAIDed iSCSI backends. And, likewise, should the NFS server go down, we can resurrect an identical clone of it from the same iSCSI backend disks and it will carry on with the state the failed one left behind.
• But where possible, use proper distributed/replicated databases!

Details

• The dom0 ISO contains a bootloader, Xen, and NetBSD set up as a dom0 kernel, with /usr/pkg containing a bunch of useful core packages (sudo, subversion-base, screen, xentools, etc)
• The dom0 ISO chain will:
  1. Mount the first partition on the first disk in the server that has a special marker file in as /config
  2. union-mount /config/local/etc/ over /etc
  3. now read /etc/rc.conf
  4. Run the normal /etc/rc tasks, including mounting /var and /tmp from the hard disk, mounting data partitions and setting up networking, ipnat, ipf, etc.
  5. Scan the list of Xen domUs to start from /config/local/domUs/* and start them, each with the correct disk images (from the data partitions), MAC address, and memory allocations.
• /config/local and /config/global are svn checkouts
• On all machines (dom0s and domUs), /etc/hosts is a symlink to /config/global/hosts, and any other such useful files.
• domUs run pkg_chk, but don't have /usr/pkgsrc; they fetch compiled binary packages from a repository domU running the same base OS, which builds every package in pkg_chk.conf. This domU might need to be the NIS master, since that would be the only way to keep pkgsrc-created role user UIDs in synch.

How to bootstrap it

• We need documented procedures for setting up a dom0 iso image, to make sure no important steps are missed...
  • Make a working directory
  • Install NetBSD source sets
  • Set up custom /etc/rc that finds a suitable filesystem to locate /etc from and mounts it as /config - or drops to a shell if none can be found.
  • Make a Xen3 dom0 kernel with "config netbsd root on cd0a type cd9660 dumps on none" and "options INCLUDE_CONFIG_FILE"
  • Put in the Xen 3 kernel
  • Configure grub menu.lst to load NetBSD on top of Xen.
  • Install core packages (xen tools) - /var/db/pkg and /usr/pkg will union mount over what we provide to allow for node-local extensions, although we shouldn't need too many in dom0.
  • Install grub and mkisofs as per http://www.gnu.org/software/grub/manual/html_node/Making-a-GRUB-bootable-CD-ROM.html
• We need domU read-only root filesystem images created along a similar theme

Subversion layout:

• /pservers/ - root of /config/local for each physical server
• /vservers/ - root of /config/local for each virtual server
• /global - /config/global
• /docs - configuration checklists and scripts for dom0 and domU master images