On Wed, Jun 25, 2008 at 11:09 PM, Jan Damborsky <[EMAIL PROTECTED]> wrote: > Thank you very much all for this valuable input. > > Based on the collected information, I would take > following approach as far as calculating size of > swap and dump devices on ZFS volumes in Caiman > installer is concerned. > > [1] Following formula would be used for calculating > swap and dump sizes: > > size_of_swap = size_of_dump = MAX(512 MiB, MIN(physical_memory/2, 32 GiB))
dump should scale with memory size, but the size given is completely overkill. On very active (heavy kernel activity) servers with 300+ GB of RAM, I have never seen a (compressed) dump that needed more than 8 GB. Even uncompressed the maximum size I've seen has been in the 18 GB range. This has been without zfs in the mix. It is my understanding that at one time the arc was dumped as part of kernel memory but that was regarded as a bug and has sense been fixed. If the arc is dumped, a value of dump much closer to physical memory is likely to be appropriate. As an aside, does the dedicated dump on all machines make it so that savecore no longer runs by default? It just creates a lot of extra I/O during boot (thereby slowing down boot after a crash) and uses a lot of extra disk space for those that will never look at a crash dump. Those that actually use it (not the majority target audience for OpenSolaris, I would guess) will be able to figure out how to enable (the yet non-existent) svc:/system/savecore:default. -- Mike Gerdts http://mgerdts.blogspot.com/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
