4 ms·
These numbers didn't ring true at all to me, even for spinning disks. And indeed, I don't think the documentation presents them with correct context - I can't f
by morelisp 3y ago
These numbers didn't ring true at all to me, even for spinning disks. And indeed, I don't think the documentation presents them with correct context - I can't figure out what's "per disk".
> A total of 3.45% of 1.53 million disks developed latent sector errors over a period of 32 months.
IOW, over 2-3 years 3.5% of disks will develop at least one error. Also,
> For most disk models, more than 80% of disks with latent sector errors have fewer than 50 errors.
- jorangreef 3y agoThanks! (and well spotted!) You're right, we had them as per disk instead of as a percentage of disks. The link was also to Bairavasundaram's Latent Sector Error analysis study instead of to their follow-up corruption analysis study (https://www.usenix.org/legacy/events/fast08/tech/full_papers/bairavasundaram/bairavasundaram.pdf https://www.usenix.org/legacy/events/fast08/tech/full_papers...), which is what we meant. I've also clarified whether these are for Enterprise or Nearline HDD. There are other studies also for flash, as well as filesystems, but Bairavasundaram was used here for illustration because of the large scale of the data, as well as the wide variety of faults covered (from LSEs through to corruption) all side by side. Here's the update: TigerBeetle recovers correctly from Latent Sector Errors (e.g. 1.4% of Enterprise HDD disks per year on average) detects and repairs disk corruption or misdirected I/O where firmware reads/writes the wrong sector (e.g. 0.466% of Nearline HDD disks per year on average), and detects data tampering with hash-chained cryptographic checksums. Would appreciate if you think we can make this still clearer.