On Dec 10, 2009, at 7:52 PM, Mark Caudill <markca at codelulz.com> wrote: > Christopher Chan wrote: >> Morten Torstensen wrote: >>> On 08.12.2009 13:34, Chan Chung Hang Christopher wrote: >>>>> Speaking for me (on Linux systems) on top of LVM on top of md. >>>>> On IRIX >>>>> as it was intended. >>>>> >>>> That is a disaster combination for XFS even now. You mentioned some >>>> pretty hefty hardware in your other post... >>> If XFS doesn't play well with LVM, how can it even be an option? I >>> couldn't live without LVM... >>> >> >> I meant it in the sense of data guarantee. XFS has a major history of >> losing data unless used with hardware raid cards that have a bbu >> cache. >> That changed when XFS got barrier support. >> >> However, anything on LVM be it ext3, ext4 or XFS that has barrier >> support will not be able to use barriers because device-mapper does >> not >> support barriers and therefore, if you use LVM, it better be on a >> hardware raid array where the card has bbu cache. > > Wait, just to be clear, are you saying that all use of LVM is a bad > idea > unless on hardware RAID? That's bad it if it's true since it seems > to me > that most modern distros like to use LVM by default. Am I missing > something? If you use a leading edge distro then they will most likely be using a LVM version with barrier support as it was implemented as of 2.6.29-2.6.30+. It should be backported by the next release of CentOS hopefully. -Ross