On 2014-04-13 01:33, John Ryan wrote:
I had a problem once where I was unable to import a pool with a missing log disk. I was unable to recover the pool. Now I mirror the logs
How long ago was that (or, rather, with how old a ZFS version)? There was this "feature" of requiring logs for import initially, but since then there appeared a command-line flag to allow pool import without processing the logs (forfeiting "sync" transactions that were only logged there). Probably this would indeed require a bit of work in single-user mode (if your pools are imported by default with /etc/zfs/zpool.cache) or soon after boot (if another pool importing mechanism is used, such as an SMF service), since on serious systems the serious decisions are by design delegated to humans - even if you can in fact automate the imports with the forcing switches in a script on your home rigs, at a risk of some conflicts (i.e. relevant on corporate shared storage) or recently written data loss (TXG rollback, log ignore, etc.) that you then won't be well informed about. Also note that if the (only) separate log device dies or is removed while the pool is up, this should be detected by the OS pretty soon and the logs would be written to main pool devices like they are on a pool without a log device at all. So the "unprotected" period in this case is relatively short, one or a few TXGs. Of course, by Murphy's law, that is bound to happen rarely - rather, your server goes down with a power surge from a lightning, and when it comes up - you discover that the log device is toast. Maybe both of them mirrored logs ;) HTH, //Jim Klimov _______________________________________________ OpenIndiana-discuss mailing list [email protected] http://openindiana.org/mailman/listinfo/openindiana-discuss
