On Sat, Apr 25, 2009 at 6:02 PM, Wojciech Puchar <woj...@wojtek.tensor.gdynia.pl> wrote: >> thinking that a software raid5 solution may not be such a bad idea. > > software raid5 isn't any more bad than hardware raid5 most cases. > > just raid5 is bad if you use it in ANY type of load except: > > a) mostly reads - then set LARGE RAID stripe size > b) mostly huge files - then set small RAID stripe size to have highest > single thread transfer, or large to have higher concurency. > > EVERY OTHER case is bad case for RAID5 - just remember small write on > RAID5=2 reads+2 writes on disks.
True, but aren't both steps done in parallel? So a single-disk equivalent is actually just one read for every write. >> The question is what port multiplier hardware does FreeBSD 7 support? > > it unfortunately doesn't. but your hardware RAID controllers drive disks by > itself and presents virtual drives to system, and system has nothing to do > with it. > so ask manufacturer if it supports port multipliers. The reason I don't want to depend on a hardware implementation is because this "server" is actually a shuttle xpc box, so not exactly built for reliability. If something breaks, I have to be able to move the disks to any other FreeBSD 7 machine and continue accessing the data. So I really just need some PCIe card and an external enclosure that will expose all attached disks to the operating system. From there I will determine how to arrange them, but I'd rather not have any controller that abstracts away the physical hard drives. - Max _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"