DragonFly users List (threaded) for 2010-03
Re: PFS mirroring insted of RAID Improved set up - need comments.
In terms of booting, if that is a worry then buy a $100 SSD and boot
from that (as well as put your swap on it and turn on swapcache,
2 for 1 deal!). You could even put root on the SSD too and use tmpfs
for /tmp. There's no real need to have RAIDed SSDs since their MTBF
is going to be approximately the same as the motherboard anyway.
Redundant multi-master HAMMER is a goal but we don't have it yet, and
we aren't thinking of it for booting in particular.
Another option is to boot off the network with a NFS root and do the
more complex local disk mounts from that basis.
The major system storage could then use a RAIDed system or a mirror
with failover... ultimately I guess a multi-master HAMMER system when
we have it. For now all we really have is vinum and a few RAID card
vendors. RAID-5 is kinda on its way out for smaller installations
because individual hard drives have gotten so large. These days you
generally just want to use a RAID 10 configuration. And for bigger
installations you buy a commercial RAID enclosure which does
everything for you and just gives you a SATA connector.
Generally speaking I'm against trying to boot off of complex storage
topologies. It results in a high potential for hitting a complexity
failure (overengineering a system to the point where it becomes so
inflexible that you can't fix it when something else breaks). And, as
I mentioned, a single $100 SSD solves the problem anyway. People
need to remember that the motherboard itself is not redundant so
frankly if you need a solution for booting you also need a solution
for a motherboard going bad.