>>>>> "Wade" == Wade Maxfield <maxfield@stripped> writes:
Wade> Well, I understand your opinion and your point.
Wade> However, raid 5 can usually be had in a hot swap
Wade> environment, and it can consume as little of 20% of the disk
Wade> resources to implement.
Wade> If my memory serves, raid 0 is striping and raid 1 is
Wade> mirroring. Mirroring uses 50% of the disk resources to
Wade> implement. The mirroring solutions I have seen requires you
Wade> to take the system down to recover. I have not seen a hot
Wade> swap mirror environment, though one may exist. I have seen
Wade> several raid 5 hot swap environments.
For PCs ? I don't know - AIX has had mirroring for some years as part
of the volume manager - hot swapping has functioned for a while IF the
hardware allowed it. We have a couple of SSA (serial storage
architecture) based systems that can either do RAID in hardware or
mirroring as part of AIX - SSA allows hot swapping. Both of these
systems have 2 machines attached to the SSA cabinett - SSA allows many
machines/disk cabinets connected in a loop - if one end of the loop
disappears all systems will automatically go the other way to get to
the disks they "own". Very nice solution I think (although it costs
more that off-the-self PC Raid systems).
To keep this Mysql related - we run Mysql on all of these systems !!
In fact there is a high availability option that allows more than one
AIX system to use the disk/filesystem at the same time - a much faster
NFS I believe, although I haven't personally tried it.
Wade> It really is up to the final customer. I prefer raid 5
Wade> over mirroring for maximum up time in the commercial
Wade> products I've seen.
Wade> wade
Adrian
