Which SCSI Adaptor and why?

[benbeneke]

We are about to purchase an IBM X235 server with the intention of having 6 x 36GB HDD in a RAID 5 array.

Which would be the better RAID adaptor, the 4MX ultra160 or the RAID 5I adaptor and more importantly - Why?

We will also need to connect an external Sony AIT tape drive.

 

[danmoran]

Straight from the docs:
ServeRAID-4Mx Ultra 160 SCSI Controller is powered by a 100MHz Intel Zion GC80303 processor that provides 64MB of battery-backed ECC cache and two internal and two external ultra 160 connections (only two connectors may be used)...
ServeRAID-5i supports both Ultra320 and Ultra160 HDD's in a dedicated or mixed environment. The adapter installs into PCI slot four and converts both channels of the onboard SCSI controller to RAID in conjunction with the LSI 1020/30 chipset. Both the standard and optional SCSI HDD backplanes cable directly to the onboard controller connectors. Half-high tape drives can be supported either internally or externally on the second channel of an integrated conroller managed by ServeRAID-5i if the bus is designated as SCSI during setup. Supports up to 528MB/s data transfers across the PCI bus with 128MB ECC SDRAM write-back cache with battery backup.

Basically, the 4Mx will leave your onboard SCSI intact to use with the tape, but is lower performance/shorter lifespan. The 5i is higher performance/longer lifespan, but uses the onboard SCSI channels, which may be good or bad, depending on your situation.

Hope this helps.