DragonFly users List (threaded) for 2011-12
Re: Which is ideal with HAMMER? softraid or hammer volume_add
Definitely not hammer volume add, that's too experimental. Soft-raid
is a bit of a joke in my view, since it typically ties you to a
particular motherboard and bios (making it difficult to physically
move disks to another machine if the mobo or psu dies), and as with
all soft-raid systems any sort of power failure during a write is
likely to cause unrecoverable data loss. Honestly I don't know of a
single system that ever had fewer failures with soft-raid than with
single disks w/ near real-time backup streams.
For HAMMER1 the best set-up is either a real raid system or no raid
at all and a master/slave server setup, depending on what is being
served. Unfortunately nothing in BSD really approaches Linux's block
level clustering and VZ container system at the moment (which is a bit of
a joke too when it comes to multiple failover events but works pretty
If you have a small system then there's no point running RAID. If you
have a larger system then there's no point running a single server.
And running RAID on multiple servers eats a lot of power so for storage
needs less than what conveniently fits on one or two disks there's no
point running RAID at all... you run redundant servers instead and use
a SSD as a caching layer in front of the slower hard drive.
For larger single-volume storage needs multiple real raid system for
primary and backup with all the insundry fallback hardware is the only
way to go. Soft-raid won't cut it.