Tekram D690CD IDE PCI Cache Controller (with RAID level 1 Mirroring and caching)
ARCO Inc. DupliDisk IDE disk mirroring controller
Support for ATA, IDE, E-IDE and UDMA drive. Controllers available can be plugged into ISA and PCI slots, and directly into the IDE controller. Furthermore, 3.5-inch and 5.25-inch Bay Mount units are available that fit into the respective drive bays. More information at Arco's web site. Make sure you have at least rev 3.00 of the firmware.
3ware Escalade IDE RAID controllers
3ware's 5000-series and 6000-series controllers have been supported since kernel 2.2.15. Support for the 7000-series controllers and RAID5 on the 6000-series controllers requires kernel 2.4.5 or 2.2.20 or better. Also make sure to use a recent firmware for RAID 5, since older firmware revisions (and older versions of the driver) can cause data corruption when a RAID 5 array runs degraded.
Adaptec ATA RAID 2400A
4-port ATA/100 controller which supports RAID 0, RAID 1, RAID 1+0, and RAID 5. Use the dpt_i2o driver, which is included in recent 2.4.x kernels.
Promise SuperTRAK SX6000
6-port ATA/100 controller which supports RAID 0, RAID 1, RAID 1+0, RAID 3, and RAID 5. Use the pti_st driver or the generic i2o drivers. Be sure to set the BIOS on the card for "Other OS" instead of "Linux", and check for firmware updates.