Safety Engineer, Dad, Husband, Pilot, Musician. Not necessarily in that order.

Ingenieur für funktionale Sicherheit, Vater, Ehemann, Pilot, Musiker. Nicht notwendigerweise in dieser Reihenfolge.

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  • 27 Comments
Joined 1 year ago
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Cake day: June 11th, 2023

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  • Then why do you think manufacturers still list these failure rates (to be sure, it is marked as a limit, not an actual rate)? I’m not being sarcastic or facetious, but genuinely curious. Do you know for certain that it doesn’t happen regularly? During a scrub, these are the kinds of errors that are quietly corrected (althouhg the scrub log would list them), as they are during normal operation (also logged).

    My theory is that they are being cautious and/or perhaps don’t have any high-confidence data that is more recent.


  • Hopfgeist@feddit.detoSelfhosted@lemmy.worldHow to fix my ZFS pool mistakes
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    8 months ago

    Bit error rates have barely improved since then. So the probability of an error whenr reading a substantial fraction of a disk is now higher than it was in 2013.

    But as others have pointed out. RAID is not, and never was, a substitute for a backup. Its purpose is to increase availability. And if that is critical to your enterprise, these things need to be taken into account, and it may turn out that raidz1 with 8 TB disks is fine for your application, or it may not. For private use, I wouldn’t fret. but make frequent backups.

    This article was not about total disk failure, but about the much more insidious undetected bit error.


  • Let’s do the math:

    The error-reate of modern hard disks is usually on the order of one undetectable error per 1E15 bits read, see for example the data sheet for the Seagate Exos 7E10. An 8 TB disk contains 6.4E13 (usable) bits, so when reading the whole disk you have roughly a 1 in 16 chance of an unrecoverable read error. Which is ok with zfs if all disks are working. The error-correction will detect and correct it. But during a resilver it can be a big problem.


  • I also use this, and it works great. Another downside is that when using the free service, others can just use subdomains of your registered domains. You can always deny it, but you have to do it manually. With the premium subscriptions you can prevent that automatically for a number of domains, depending on how much you pay.


  • To add, unlike “traditional” RAID, ZFS is also a volume manager and can have an arbitrary number of dynamic “partitions” sharing the same storage pool (literally called a “pool” in zfs). It also uses checksumming to determine if data has been corrupted. On redundant setups it will then quietly repair the corrupted parts with the redundant information while reading.




  • Hopfgeist@feddit.deOPtoSelfhosted@lemmy.worldDifferent "geometries" for same disk model?
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    1 year ago

    Sure, SCSI disks will show their defective list (“primary defects”, as delivered by the factory, and grown defects, accumulated during use), and they all have a couple hundred primary defects. But I don’t see why that would affect the reported geometry, given that it is fictional, anway. And all disks have enough spare tracks to accommodate for the defects, and offer the specified full number of total sectors, even for long list of grown defects. Incidentally, all the 4TB disks are still “perfect” in that they have no grown defects.

    And yes, ever since LBA, nobody has used sectors and cylinders for anything.


  • I’m not touching that post again. But a small rant about typesetting in lemmy: It seems there is no way whatsoever to put angle brackets in a “code” section. In an overzealous attempt to prevent HTML injection, everything in angle brackets is just removed when posting (although it remains there in preview). In normal text, you can use “<”, but not inside “code” segments, where it will be retained verbatim.



  • If you want a proper server, it seems that Asrock Rack is the only manufacturer of AM4-socket-based server mainboards. Unlike desktop/gamer boards, these are designed for parallel airflow, typically from front to back in a 19" rack. These also come with IPMI remote maintenance, so can be operated headless in a remote location.

    I have considered one of these for a while, such as the X570D4U, which also supports up to 128 GB of ECC RAM. Depending on what you want, this may be overkill, though.

    (This was my favourite, because it has two M.2 slots, but there are others with only a single slot, since you said you only need one.)

    Unlike gamer or other boards, these have no fancy black vanity covers and often won’t allow overclocking, but are typically very well designed and rock solid for unattended 24/7 operation.





  • It’s much more than a fan shroud. It’s a baffle specifically designed to guide cooling air over the CPU heatsinks and the RAM modules. This kind of airflow design is very common in servers. I wouldn’t trust it without, especially since the CPU heatsinks have no dedicated fans, but rely on the aerodynamic functioning of the baffle.

    And yes, I know they are very similar, in fact I am quite (but not absolutely) certain that they are identical except for the actual second CPU socket. It’s almost as if you didn’t read my post. Even the soldering points for the second CPU socket are there in the single-CPU T320. They certainly won’t have different PSU connectors. They even share part numbers for the case.




  • Not so much server-based, but the experimental part of “lab” is well covered: I replaced my late-2013 27" iMac’s internal HDD with an SSD. It’s a really delicate procedure, as the display is glued to the chassis; it needs to be cut loose and very carefully removed (it’s tempered glass), and then re-glued with special adhesive strips. But the performance gain is worth it. In addition, it also now runs Ventura, even with the nVIDIA card, thanks to OpenCore Legacy Patcher. Feels like a new machine now, and is perfectly adequate even for small video editing tasks with its 32 GB RAM.


  • I don’t think there’s anything intrinsically wrong, but far as I can see you are using only a single disk for the zfs pool, which will give you integrity checks (know when something is corrupted), but no way to fix it.

    Since this is, by today’s standards, a tiny disk at 100G, I assume this is just a test setup? I’m not sure zfs is particularly well suited for virtual machines, I think it is better to have the host handle the physical data integrity by having the disk image on a zfs filesystem, or giving the VM a zfs volume (block device) directly.