On 02/02/09 17:50, Ferenc Wagner wrote: > Laurent Grawet <[email protected]> writes: > >> The default PE size is too small (4MB) for some use when creating >> volume groups (VG) with debian-installer. >> >> If you're dealing with large amounts of data, it is highly >> suggested to go for a larger extent size for performance reasons. > > man vgcreate says: > > If the volume group metadata uses lvm2 format those restrictions do > not apply, but having a large number of extents will slow down the > tools but have no impact on I/O performance to the logical volume. > > Thus I don't find it 'highly suggested'. What do you base your > statement on?
I read it here and there some time ago and took it as best practice. For example : "Reducing the physical extent size increases the size of the LVM data structures but gives a finer granularity for assigning storage to logical volumes. Increasing the physical extent size slightly reduces the LVM overhead, increasing performance." http://codeidol.com/unix/fedora/Advanced-Installation/Configuring-RAID-and-LVM-During-Installation/ The man page seems to prove I was wrong. Maybe it applied only to LVM1 (like small PE limit per VG). I'm still wondering why Red Hat set it to 32 MB by default. Laurent -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
