Today, I was reminded that at one point I had strong feelings on the issue of PS/2 versus USB for keyboardsand mice, where I didn't like USB keyboards and my preferred mouse (or varietyof them) was also a PS/2 mouse. However, these days I am entirelyUSB based for both keyboard and mouse and I don't particularly wantto go back. What got me here is an assortment of issues, includingthe relentless march of time and 'progress' in the

When we upgraded from Ubuntu 18.04 to Ubuntu 22.04, we moved awayfrom the prefork MPM to the event MPM .A significant reason for this shift is that our primary publicweb server has woundup with a high traffic level from people downloading things, oftenrelatively large datasets ( for example ). My intuition wasthat much of the traffic was from low-rate connections that weremostly idle on the server as they waited for slow remote networks.The event MPM is supposed to

As you may have heard, Github changed its RSA SSH host key today ,because the private key had been exposed (apparently briefly) in apublic Github repository. As a result of this, a lot of people gotscary looking SSH warnings. One reaction people had to this was tonote that Github could have avoided these warnings if it had used OpenSSH host key rotation toprovide a second RSA host key in advance to prepare for the rotation.However, there is one little issue with this, which I alluded

I'll put the summary up front. If you have SSD based systems installedwith a reasonably modern Linux, it's pretty likely that they arequietly automatically discarding blocks from your SSDs on a regularbasis. This is probably true even if you use software RAID mirrors(despite the potential problem RAID has with discarding blocks ).

To start with, you can see if your SSDs are capable of discardingblocks with ' lsblk -dD '. If block discard is possible, it will reportsomething like:

;

One of the things that's good for the performance of modern SSDsis explicitly discarding unused blocks so the SSD can erase flashspace in advance . My impression is thatmodern SSDs support this fairly well these days and people considerit relatively trustworthy, and modern filesystems can discard unusedblocks periodically (Linux has fstrim , which issometimes enabled by default). However, in some environments there'sa little fly in the ointment, and that's RAID (whether software or'hardware').

The issue

One part of a NFS filehandle isan identification of the filesystem (or more accurately the mountpoint) on the server. As I've seen recently there are various formsof (NFS) filesystem IDs , and they caneven vary from client to client (although you shouldn't normally set things up that way). However,all of this still leaves an open question for ZFS on Linux filesystemsin specific, which is where does the filesystem ID come from andhow can you work it out, or

Recently over on the Fediverse, someone who's coming back to Linuxasked what terminal program one should use these days. After thinkingabout it, I realized that my answer had to be Gnome Terminal ( also ), at least for thekind of person who's asking this question without any particularadditional qualifiers.

I'm personally very attached to the venerable xterm, but xtermis an acquired taste with various issues in practice, so I can'trecommend it to a new person. If you want

Over on the Fediverse, I had a Grafana and Prometheus wish :

I wish Prometheus could tell Grafana what the scrape interval for ametric is, so Grafana could always set a sensible minimum interval fordashboard panels.

This thought is brought to you by changing entirely too many panelsbecause I changed from 15s to 30s scrapes for our most verbose set ofmetrics (the ZFS exporter, which has many histograms).

In many cases, visualizing Prometheus metrics will require you touse rate() or maybe

Recently I shared a modern Unix superstition on the Fediverse :

Is it superstition that I do 'dd if=... bs= | cat>/dev/null' instead of just having 'of=/dev/null' because I'm cautiousabout some version of dd optimizing that command a little toomuch? Probably.

There are various things you could say about this, but thinking aboutit has made me realize that in practice, there are two facets to dd ,what you

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