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

[Luca Ferrari]

On Wednesday 16 January 2008 Ruben Laban's cat, walking on the keyboard, 
wrote:
> Depending on the database usage of that server, RAID5 might not be the
> solution you want to go for. RAID5 has the downside of 'expensive' writes.
> If storage is less important than speed, I suggest you go for either RAID10
> or RAID0+1 (mirrored stripe versus striped mirror). Using LVM over both the
> RAID1 and RAID5 as you suggested doesn't make much sense to me.
> Using LVM in general has its pros and cons. Pro being that you can
> repartition 'safely' on-the-fly, con being that it might introduce a
> performance hit.
>

Thanks,
our priority is storage, without having a too bad speed, that's why I was 
thinking of a raid5. In this sense even raid10 is good, but this means I'll 
have half the space. About LVM, I could use it only for the file storage and 
not for the database one, this could give me good database performances 
against the capability to resize the file server space (that is not related 
to the database). 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?

Luca