[linux-lvm] Performance impact of LVM

[Mark H. Wood]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Some uses of LVM *could* increase I/O wait time.  It's easy to paste new 
extents onto existing volumes, and the new extent probably won't be 
contiguous with the old one.  So you *could* see longer average seek 
delays due to additional arm travel distance between extents.  It's 
strongly dependent on access patterns.

However this effect is probably down in the noise for most systems.  The 
only way to know if it's a problem for you is to measure.  I would expect 
that, given contemporary amounts of caching on the drive, the controller, 
and in the OS, you probably won't see it unless you are driving your 
storage *really* hard.  If you do, dump/recreate contiguously/restore will 
make it go away.

- -- 
Mark H. Wood, Lead System Programmer   mwood at IUPUI.Edu
Typically when a software vendor says that a product is "intuitive" he
means the exact opposite.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.4 (GNU/Linux)
Comment: pgpenvelope 2.10.2 - http://pgpenvelope.sourceforge.net/

iD8DBQFEygj6s/NR4JuTKG8RAsiUAJ4rfE9pWkHQjjl1W5DGLV2jaHCyegCgn+fO
umxX1nQ9djK5wa2/n93FKLc=
=7ev8
-----END PGP SIGNATURE-----