raid and lvm with 8 disks....suggestions?

[Luca Ferrari]

On Wednesday 16 January 2008 Ruben Laban's cat, walking on the keyboard, 
wrote:
> On Wednesday 16 January 2008, Luca Ferrari wrote:
> > But a doubt I've got is about the raid array: if I make an
> > LVM partition on the raid5 array (saying it is raid5), and then I decide
> > to add a new disk (so adding it thru LVM), can I add it to the array too?
>
> Adding an extra disk to an existing LVM volume group isn't a problem, it's
> one of its features actually.
>
> Adding an extra disk to an existig raid array might or might not be
> possible. This depends on the capabilities of your raid controller. It's
> possible for instance with linux' software raid, but the tools required are
> far from production ready. Cheaper raid cards most likely won't offer this
> feature.


How does it sounds a system like this:
4 disks in raid 10 for the database and the main system
4 disks in raid5 (one spare) for the file server

Could it be a good compromise between performance and security?
About LVM, at least it is possible to build another small array with 
additional disks, thus I could add with LVM such disks (of course in the 
space of the file server)....

What do you think?

Luca