Hi Jeff,
Jeff Bonwick wrote: >> Neither swap or dump are mandatory for running Solaris. > > Dump is mandatory in the sense that losing crash dumps is criminal. I think that installer should be tolerant in this point and shouldn't refuse to proceed with installation if user doesn't provide enough available disk space to create dump device. It should be probably documented (for example mentioned in release notes) that when minimum disk space is provided for installation, swap & dump are not created. > > Swap is more complex. It's certainly not mandatory. Not so long ago, > swap was typically larger than physical memory. But in recent years, > we've essentially moved to a world in which paging is considered a bug. > Swap devices are often only a fraction of physical memory size now, > which raises the question of why we even bother. On my desktop, which > has 16GB of memory, the default OpenSolaris swap partition is 2GB. > That's just stupid. Unless swap space significantly expands the > amount of addressable virtual memory, there's no reason to have it. I agree with you in this point. Since new formula for calculating swap & dump will take into account amount of physical memory, the values should make more sense. That said, this is just default value and certainly wouldn't be feasible in all situations. However, as this is something which can be changed at will after installation is done, I would rather keep that formula as simple as reasonable. > > There have been a number of good suggestions here: > > (1) The right way to size the dump device is to let dumpadm(1M) do it > based on the dump content type. To be honest, it is not quite clear to me, how we might utilize dumpadm(1M) to help us to calculate/recommend size of dump device. Could you please elaborate more on this ? > > (2) In a virtualized environment, a better way to get a crash dump > would be to snapshot the VM. This would require a little bit > of host/guest cooperation, in that the installer (or dumpadm) > would have to know that it's operating in a VM, and the kernel > would need some way to notify the VM that it just panicked. > Both of these ought to be doable. Yes - I like this idea as well. But until the appropriate support is provided by virtual tools and/or implemented in kernel, I think (I might be wrong) that in the installer we will still need to use standard mechanisms for now. Thank you, Jan _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
