Darren, Thanks for the explanation. Would you object if I opened a bug on the zfs man page to include what you've written here ?
Thanks again, John Darren J Moffat wrote: > John Cecere wrote: >> The man page for dumpadm says this: >> >> A given ZFS volume cannot be configured for both the swap area and the >> dump device. >> >> And indeed when I try to use a zvol as both, I get: >> >> zvol cannot be used as a swap device and a dump device >> >> My question is, why not ? > > Swap is a normal ZVOL and subject to COW, checksum, compression (and > coming soon encryption). > > Dump ZVOLs are preallocated contiguous space that are written to > directly by the ldi_dump routines, they aren't written to by normal ZIO > transactions, they aren't checksum'd - the compression is done by the > dump layer not by ZFS. This is needed because when we are writing a > crash dump we want as little as possible in IO the stack. > > -- > Darren J Moffat -- John Cecere Americas Technology Office / Sun Microsystems 732-302-3922 / [EMAIL PROTECTED] _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
