We have a large MySQL database currently running on a CentOS 3.x server with an external SCSI RAID device. This is currently an ext2 filesystem because it was migrated once previously from an even older RedHat system. We need to add storage capacity to this database and prepare for additional future growth. One of the options under consideration is to move to CentOS 5 and use LVM. Of some concern is that we run some pretty heavy-duty queries against this database in close to real time, so we don't want the switch to scalable storage to have a significant impact on read latency. Consequently I'm looking for sources of information on two topics: - What kind of performance can we expect from an LVM group as compared to mounting the RAID array directly? - What's involved in migrating our filesystem from ext2 to LVM with a minimum of downtime? Thanks in advance for directions.