> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of Jim Klimov > > And regarding the "considerable activity" - AFAIK there is little way > for ZFS to reliably read and test "TXGs newer than X"
My understanding is like this: When you make a snapshot, you're just creating a named copy of the present latest TXG. When you zfs send incremental from one snapshot to another, you're creating the delta between two TXG's, that happen to have names. So when you break a mirror and resilver, it's exactly the same operation as an incremental zfs send, it needs to calculate the delta between the latest (older) TXG on the previously UNAVAIL device, up to the latest TXG on the current pool. Yes this involves examining the meta tree structure, and yes the system will be very busy while that takes place. But the work load is very small relative to whatever else you're likely to do with your pool during normal operation, because that's the nature of the meta tree structure ... very small relative to the rest of your data. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
