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lathiaton 6 Raspberry Pis, 6 SSDs on a Mini ITX Motherboard

The async messenger has gotten the thread counts way down. May be a little easier now.

lathiaton A laptop hard drive model could crash when exposed to a certain audio frequency

EEVBlog made a video demonstrating that and explaining it generally: https://youtu.be/SrDfRCi1UV0

lathiaton 6 Raspberry Pis, 6 SSDs on a Mini ITX Motherboard

Weekly scrub errors are definitely not normal. There has been a few bug fixes in Ceph & the Kernel. I would check how up to date your packages are.

Hardware errors are also possible but there has been a few software bugs so worth checking.

Here's a really curly one we recently found and solved at work (only in March) that causes both scrub errors and sometimes bluefs aborts, it's a kernel patch. Likely to happen under memory pressure:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...

https://tracker.ceph.com/issues/22464#note-50

But there have been various others.

lathiaton 6 Raspberry Pis, 6 SSDs on a Mini ITX Motherboard

For the standard 3x replicated setup, 3 nodes is the minimum for any kind of practical redundancy but you really want 4 so that after failure of 1 node all the data can be recovered onto the other 3 and still have failure resiliency.

For erasure coded setups which is not really suited to block storage but mainly object storage via radosgw(s3) or cephfs you need minimum k+m and realistically k+m+1. That would translate to 6 minimum but realistically 7 nodes for k=4,m=2. That’s 4 data chunks and 2 redundant chunks which means you use 1.5x the storage of the raw data (half that of a replicated setup). You can do k=2,m=1 also. So 4 nodes into that case.

lathiaton 6 Raspberry Pis, 6 SSDs on a Mini ITX Motherboard

That’s called ceph scrub & deep-scrub.

By default it “scrubs” basic metadata daily and does a deep scrub where it fully reads the object and confirms the checksum is correct from all 3 replicas weekly for all of the data in the cluster.

It’s automatic and enabled by default.

lathiaton 6 Raspberry Pis, 6 SSDs on a Mini ITX Motherboard

Try https://rpilocator.com/ - no promises though.

lathiaton 6 Raspberry Pis, 6 SSDs on a Mini ITX Motherboard

110MB/s is gigabit. It’s limited to gigabit networking and only has 1Gbps out from the cluster board. So there’s no way to do an aggregate speed of more than 1Gbps/110MBs on this particular cluster board.

If each pis Ethernet was broken out individually and you used a 10G uplink switch or multiple 1G client ports then you could do better.

The write speed being lower than the read speed will be because writes have to be replicated to two other nodes in the ceph cluster (everything has 3 replicas) which are also sharing bandwidth on those same 1G links. Reads don’t need to replicate so can consume the full bandwidth.

So basically it’s all network limited for this use case. Needs a 2.5G uplink, LACP link aggregation or individual Ethernet ports to do better.

lathiaton Ask HN: Can I see your scripts?

For pwgen there is a great tool of the same name that does basically that. Just have to add -1 to get a single password by default it outputs a whole bunch so you can pick one which I prefer most of the time.

lathiaton Tell HN: After 10 years of experiments, custom username emails receive no spam

Depends if they get breached haveibeenpwned.com style. I definitely and clearly get spam from several breaches. Some is generic (it’s on some big spam list) and some of it is targeted - like crowd funding campaigns spamming the hacked list of kickstarter accounts - which I am surprised how much of I get given how community driven such things often but I guess are not always.

Some of these addresses were the unique style you mentioned.

So I guess you’re just lucky.

lathiaton The Remote Pop-In (2021)

Spaceballs…

“Hey, I told you not to call me on this wall. This is an unlisted wall!”

lathiaton Covid face masks devastating bird populations around the world

https://flomask.com/

Reusable. Seals properly. Incredible breathability. Doesn’t hurt your ears.

Main downside is speech is not the most amazing. You also get a bit of condensation.

Love mine. Also cuts the waste and has no elastic to trap the birds

lathiaton Run FreeBSD 13.1 for ARM64 in QEMU on Apple Silicon Mac with HVF Acceleration

Pretty much!

lathiaton Google Timer is gone

That still works thanks :)

lathiaton Google Timer is gone

You used to be able to search “ip address” and get it direct. That also disappeared maybe a year or so ago. Annoying as all the other major hits at covered in ads.

lathiaton Binary Translators for Weak Memory Model Architectures

This ("TSO") is actually an ARM standard however its only very latest ARM (v8.4-v8.7) and not many other CPU implementation currently. AWS Graviton 3 and maybe very latest phone SoCs if I understand correctly.

https://news.ycombinator.com/item?id=31664688 https://twitter.com/marcan42/status/1534053625110351872 https://twitter.com/never_released/status/153412764108259328...

lathiaton Ask HN: YouTube Channels for the Intellectually Curious

Engineering Explained does a lot of real math on car related topics while also being interesting. https://youtube.com/user/EngineeringExplained

Michel Van Bizen has hundreds (thousands?6 of university level lectures on many topics science and math: https://youtube.com/c/MichelvanBiez

Discovered that channel trying to understand all modes of heat transfer through windows. Covered under thermodynamics. https://youtu.be/r3tC-ocdVoQ

lathiaton DwarFS: A fast high compression read-only file system

Sounds like the main benefit is hash-based dedup. You can do this with ZFS and borgbackup - they'd likely be a better comparison - but most other compressed filesystems won't do it.

Most compressed filesystems will fail to dedup stuff because for various performance related reasons the compression window is usually quite small maybe up to 128kb and the files are often not sorted in the archive such that small files would manage to compress anyway in that window.

EDIT: Apparently squashfs does include file de-dupe however DwarFS is fixing what I basically said above. It sorts files in order of similarity so that you can compress accross file boundaries as well as just removing complete duplicates. That's pretty cool.

"Clustering of files by similarity using a similarity hash function. This makes it easier to exploit the redundancy across file boundaries."

This kindof thing is more difficult to do on a writable filesystem though not impossible.

lathiaton Xz format considered inadequate for long-term archiving (2016)

It is a case that will happen, when you long-term archive files. Which is exactly what the article discusses. Bit-rot is a real thing that really happens. The argument makes the case that XZ is a poor choice for such a case where you possibly have only one copy and can't just download a new un-corrupted copy.

lathiaton Xz format considered inadequate for long-term archiving (2016)

I recently came to the same determination looking for a better way to package sosreports (diagnostic files from linux machines). The pieces are there for indexed file lists and also seekable compression but basically nothing else implements them in a combined fassion with a modern compression format (mainly zstd).

lathiaton Why does the M1/M2 only support one external display?

Try “Lunar” it lets you control brightness and volume using the system keys on most but not all monitors: https://lunar.fyi/

lathiaton Cooling related failure (in Google London DC)

Guessing you’re from the UK where you seem to have fancy pre configured sub boards. In Australia the standard and 99% of house installs are just hand wired with single wires from breaker to breaker and they’re twisted together and rammed into the bottom of the breakers :)

lathiaton A Windows 95-like shell for Windows 3.1x

Me too :)

I remember that apparently for desktop applications icons to work it had to launch a process just to be each icon so was quite memory intensive. I seem to recall it also requiring “win32s”

My machine would throw a text mode confirmation prompt over the win95 graphical installer when it tried to write the boot sector as boot sector virus protection and this would freeze the system so windows 95 installation never worked.

lathiaton Systemd Creator Lands at Microsoft

Did you actually use Linux audio before pulse audio?

It sure was great only using sound from one application at once.

lathiaton Ask HN: Which password manager do you use?

BitWarden. Switched from LastPass because it basically got no updates for 5+ years and was a bit clunky.

lathiaton DigitalOcean Restricts SMTP

Almost certainly just means an SMTP Relay (or at least an email sending API). Sendgrid, Amazon SES, Etc

lathiaton 7-zip 22.00 – APFS, Posix TAR, high precision timestamps

Intel out-of-tree NIC drivers too; https://sourceforge.net/projects/e1000/ - But there are not many!

lathiaton Contra Wirecutter on the IKEA air purifier

Australia: https://www.choice.com.au/ New Zealand: http://consumer.org.nz/

lathiaton SpaceX said to fire employees involved in letter rebuking Elon Musk

You nailed that on the head.

lathiaton Safari on iOS can overlap multiple full-screen videos

I always assumed this was part of their deal with records companies to basically prevent people using YouTube as a free music streaming service (while keeping music videos there). Partly because before iOS added picture-in-picture they had a feature to enable videos to keep playing as audio only in the background but ONLY if you had YouTube Red/Premium.

Having said that, they now enabled Picture-in-Picture on iOS (though last check it's still in beta I joined the beta a while back) and one of Apple's requirements is you cannot but OS features (such as Picture in Picture) behind an app paywall. So they could only do this by making it available to everyone including free users. Not sure what got them over the line but its there now.

So makes me wonder if that will go away - or whether they still enforce that requirement on Android, or what.

lathiaton Quick Tip: Enable Touch ID for Sudo (2020)

Every time you type a password or pin code into your phone in a public place it’s trivial for someone to see what it is over your shoulder. It’s doable for keyboards to though not quite as easy.

They can’t see it if you use your fingerprint or FaceID.

That’s actually a security improvement for some threat models.

Just a thought :)