Many years ago I wrote a couple of entries about ZFS's ZILoptimizations for writes and then an update forseparate log devices . In completely unsurprisingnews, OpenZFS's behavior has changed since then and gotten simpler.The basic background for this entry is the flow of activity inthe ZIL (ZFS Intent Log) .

When you write data to a ZFS filesystem, your write will be classifiedas 'indirect', 'copied', or 'needcopy'. A 'copied' write is immediatelyput into

One of the slow discussions I'm involved in over on the Fediversestarted with someone wondering what modern GPU to get to run Linuxon Wayland (the current answer is said to be an Intel Arc B580, ifyou have a modern distribution version). I'm a bit interested inthis question but not very much, because I've traditionally consideredbig discrete GPU cards to be vast overkill for my needs. I use anold, text-focused type of X environment and I don

Every so often my thoughts turn to absurd ideas. Today's absurdidea is sparked by my silly systemd wish for moving processesbetween systemd units , whichin turn was sparked by a local issue with Apache CGIs (and suexec).This got me thinking about what a modern 'multi-user' web serverwould look like, where by multi-user I mean a web server that'sintended to serve content operated by many different people (suchas many different people's CGIs). Today you

One of the pieces of news of the time interval is (GNOME is)Introducing stronger dependencies on systemd ( via ).Back in the old days, GNOME was a reasonably cross-platform Unixdesktop environment, one that you could run on, for example, FreeBSD.I believe that's been less and less true over time already (although the FreeBSD handbook has no disclaimers ), but GNOMEadding more relatively hard dependencies on systemd really puts astake in it, since systemd is emphatically Linux-only.

Argparse is thestraightforward standard library module for handling command linearguments, with a number of nice features. One of those nice featuresis groups of mutually exclusive arguments . Ifpeople can only give one of '--quiet' and '--verbose' and bothtogether make no sense, you can put them in a mutually exclusivegroup and argparse will check for you and generate an appropriate error. However, mutuallyexclusive groups have a little limitation that makes me sad.

Suppose, not hypothetically, that you have

Over on the Fediverse, Simon Tatham had a comment about (using)cloud identity providers that's sparkedsome discussion. Yesterday I wrote about the facets of identityproviders . Today I'm sort of writingabout why you might not want to run your own identity provider,despite the hazards of depending on the security of some outsidethird party. I'll do this by talking about what I see as beinginvolved in the whole thing.

The hardcore option is to rely on no outside services at all,

Over on the Fediverse, Simon Tatham had a comment about cloudidentity providers ,and this sparked some thoughts of my own . One of my thoughtsis that in today's world, a sufficiently large organization mayhave a number of facets to its identity provider situation (whichis certainly the case for my institution ).Breaking up identity provision into multiple facets can leave itnot clear if and to what extend you could be said to be using a'cloud identity provider'.

First off, you may outsource '

Linux cgroups offer a bunch of robust features for limiting resourceusage and handling resource contention between different groups ofprocesses, which you can use to implement things like per-usermemory and CPU resource limits . On asystemd based system, which is to say basically almost all Linuxestoday, systemd more or less completely owns the cgroup hierarchyand using cgroups for resource limits requires that the processesinvolved be placed inside relevant systemd units, and for thatmatter that the systemd units exist.

Unfortunately, the mechanisms for doing this are

Every so often I have some Python code where I have a collectionof functions and along with the functions, some additional informationabout them. For example, the functions might implement subcommandsand there might be information about help text, the number of commandline arguments, and so on. There are a variety of approaches forthis , but a very simple one I'vetended to use is to put one or more additional attributes on thefunctions. This looks like:

def dosomething(....):