On Thu, Jun 25, 2015 at 12:57 PM, Mikael <[email protected]> wrote: > For having a *guaranteedly intact* storage, what is the way then? > > This is with the background of recent discussions that touched on > https://www.usenix.org/legacy/events/fast08/tech/full_papers/bairavasundaram/bairavasundaram_html/index.htmland > https://blog.algolia.com/when-solid-state-drives-are-not-that-solid/ . > > > > What about having *two SSD*:s in softraid RAID1, and as soon as any IO > failure is found on either SSD, that one would be replaced? > > If the underlying read operations are made from both SSD:s each time and the > machine has ECC RAM (??and UFS is checksummed enough??), then at least the > OS would be able to detect corruption (??, fix anything??) and return proper > read failures (or sigsegv) properly.
I'm afraid that as far as SSD is not signalling any issue you may end with corrupted data in the RAM and even softraid RAID1 will not help you. AFAIK FFS does not provide any checksumming support for user data so this is the same issue again. I've tinkering with an idea to enhance softraid RAID1 with checksumming support. Currently reading papers and code to grasp some knowledge about the topic. The thread is here: https://www.marc.info/?l=openbsd-tech&m=143447306012773&w=1 -- if you are quicker than me implementing it, then great! I'll probably switch to some other task in OpenBSD domain. :-) Cheers, Karel
