Low I/O performance of PERC 4/DC on PE2650

["Kadirvel, Selvi" <selvik@xxxxxxx>]

We use a PERC 4/DC card on a PowerEdge 2650 server. Connected to 
each SCSI bus is a set of 14 physical disks. Using the Dell 
Manager utility we create RAID 0 (logical) disk with 4-way stripes 
i.e 4 physical disks(across the two channels) and 128K block size. 
Using I/O benchmark applications like IOzone, the maximum 
throughput obtained is only about 100 MBps. We get lower values 
for other stripe sizes and block sizes. Shouldn't this be higher, 
considering that the SCSI bus provides 320 MBps throughput ? Does 
anyone know how to get better performance?

Thanks.
-Selvi


-
: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html