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“Ultimately the Operating System doesn't (and can't) know whether the storage is actually going to retain data you've written to it.” illumos and ZFS do know a

“Ultimately the Operating System doesn't (and can't) know whether the storage is actually going to retain data you've written to it.” illumos and ZFS do know about it, especially since ZFS will checksum every block and will perform an explicit flush for every write. Should the drive lie about it, the checksum won’t match. To make the claims you made just because what I wrote doesn’t involve Linux is preposterous. Sun engineers spent 25 years making the OS robust and able to correctly cope with failing, flaky or otherwise unreliable hardware. Ever heard of fault management architecuture in Solaris? If you had, you wouldn’t have written what you wrote.

tialaramex 8y ago
"illumos and ZFS do know about it" They literally can't, as I explained previously. Everything seems fine with such hardware, up until you find that some of the data you were absolutely sure you'd written isn't there after all. The fact you can't conceive of how this goes wrong is actually _illustrative_ of how Sun got screwed. The foolish man certainly does build his house on sand. Now, twenty five years ago when those Sun engineers apparently started making the OS robust (maybe this explains how it got the reputation for being a flaky piece of crap, they should have started sooner...) I was working for a company that I'm quite _sure_ a person who says they really care about robust systems has heard of. Tandem Computers. Tandem had a demo that gets to the heart of the thing you think you really care about in Illumos. Do a transaction, it's committed, and then we... pull out the CPU cards from the computer. It's dead. ... and our transaction is safe and indeed other users can continue to use the system, with the committed transaction, because it was replicated to other nodes far away and those weren't destroyed. Tandem Computers doesn't exist any more because it turns out that doing this correctly is expensive and nobody wants to pay extra for correctness. After all, Sun engineers said their OS is "able to cope with failing, flaky or otherwise unreliable hardware" and with the lower price tag a customer really wants to believe that's true, shame about their data when it isn't...
- Annatar 8y ago
  “The fact you can't conceive of how this goes wrong is actually _illustrative_ of how Sun got screwed.“ I can very well concieve of it, as I’ve been preaching this to the Linux crowd for decades and they just don’t get it. By the way I know about Tandem because yes, I’m that old. Please, before you go preaching to the choir (me), read how ZFS works; if the drive totally completely lies about everything, if it silently corrupts data, first read from the drive will uncover it because the checksums won’t match. ZFS will still deliver good data if it has redundant copies and will attempt to overwrite the corrupt data automatically. 50% of the two memory chips in my Solaris storage server no longer function correctly; Solaris has automatically migrated the affected pages out of them. When I get new memory chips, I will off-line them and replace them. Tandem might have been even more robust, but its engineers didn’t continue working on it after the company’s demise like those Sun engineers did on illumos.

tialaramex 8y ago

"illumos and ZFS do know about it" They literally can't, as I explained previously. Everything seems fine with such hardware, up until you find that some of the data you were absolutely sure you'd written isn't there after all. The fact you can't conceive of how this goes wrong is actually _illustrative_ of how Sun got screwed. The foolish man certainly does build his house on sand. Now, twenty five years ago when those Sun engineers apparently started making the OS robust (maybe this explains how it got the reputation for being a flaky piece of crap, they should have started sooner...) I was working for a company that I'm quite _sure_ a person who says they really care about robust systems has heard of. Tandem Computers. Tandem had a demo that gets to the heart of the thing you think you really care about in Illumos. Do a transaction, it's committed, and then we... pull out the CPU cards from the computer. It's dead. ... and our transaction is safe and indeed other users can continue to use the system, with the committed transaction, because it was replicated to other nodes far away and those weren't destroyed. Tandem Computers doesn't exist any more because it turns out that doing this correctly is expensive and nobody wants to pay extra for correctness. After all, Sun engineers said their OS is "able to cope with failing, flaky or otherwise unreliable hardware" and with the lower price tag a customer really wants to believe that's true, shame about their data when it isn't...

Annatar 8y ago
“The fact you can't conceive of how this goes wrong is actually _illustrative_ of how Sun got screwed.“ I can very well concieve of it, as I’ve been preaching this to the Linux crowd for decades and they just don’t get it. By the way I know about Tandem because yes, I’m that old. Please, before you go preaching to the choir (me), read how ZFS works; if the drive totally completely lies about everything, if it silently corrupts data, first read from the drive will uncover it because the checksums won’t match. ZFS will still deliver good data if it has redundant copies and will attempt to overwrite the corrupt data automatically. 50% of the two memory chips in my Solaris storage server no longer function correctly; Solaris has automatically migrated the affected pages out of them. When I get new memory chips, I will off-line them and replace them. Tandem might have been even more robust, but its engineers didn’t continue working on it after the company’s demise like those Sun engineers did on illumos.