disable multi-threaded dump
Joyent, EC, and several others have reported hangs while taking crash dumps on multi-core machines.
Experimentally, this appears to be due to a bug in the threaded dump support.
We should seriously consider disabling threaded dump until someone has a chance to fix it
* * Don't use multi-threaded fast crash dump or a high compression level * set dump_plat_mincpu=0 set dump_bzip2_level=1
From Joyent's overlay. I'm unsure on whether the bzip2 limit is related.
I don't know of any progress on debugging this, due to the inherent difficulty in doing so.
Updated by Garrett D'Amore about 9 years ago
I think multithreading dump (especially since this is usually done at panic time) is a bad idea. When bad stuff happens, you want to get the data, and then get back into service reliably. You can't trust anything about the system during panic, and running MT seems like a bad idea with lots of potential for grief. (For the record, this is also why I'm opposed to using fast-reboot-on-panic... You want a real POST after a panic.)