[linux-lvm] Performance measures with LVM. Idem with LVM & RAID (linux)

[RoMaNSoFt]

 Hi,

 I guess this question should be a faq but I haven't found any recent
document/paper explaining the performance penalties implied by a
typical small-scenario LVM installation.

 In particular I have a SuSE 8 linux in a 1 GHz processor box, with a
13 gb "normal" ide disk. I have another hd that, if necessary, I will
use in a future to expand partitions. So I had thought of using LVM
(scalability purposes). But before installing it, I'd like to have a
look to any recent paper/doc/article talking about the performance of
LVM. Beside this, I'd also like to know about the performance of a LVM
over (software-) RAID system. Is there any kind of comparative or
benchmarking about typical IDE systems with LVM (recent version) (and
with/without RAID)?

 Ups, I forgot it: I'm always refering to LVM in linear mode
(non-stripped mode), with each disk containing one PV.

 Summarizing:
 Which % of penalty will I suffer if I install LVM? Which kind of
operations would be more affected? I read about 1% penalty and "dd"
operations being the worst cases. Could you confirm it?

 Thanks in advance and sorry if this is a faq...

 Salu2,
 --Roman

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