ok #freebsd and #zfs mastodon people. Answer me this, I have a ZFS filesystem on machine A, I zfs-send it to machine B (zfs send -R) (zfs receive -Fv). machine A has 4T of space *total*. machine B has 8T of space. when done, machine B has only 250g of free space available), the filesystem is almost _twice_ as large?
@david is the record size the same? If your source uses larger than 128K records and you didn't use -L it may be using 128K records on the target (they incur larger overhead than larger records do). I saw this when moving a zvol with 1M records to one with 128K records.
@javierk4jh My understanding from reading zfs-send and zfs-receive and online searches is that you actually cannot change recordsize that way as the stream is deltas itself.
That is if the incremental says to "set block 15 to 0xfeedface", then block 0xfeedface doesn't have the context of the rest of the block to fill in.
Granted this is a solvable problem to just read the original and write out the whole, but they opted to not have that complexity
I did check anyway, and recordsizes look good
