FCP/SCSI devices are faster than FICON/ECKD devices. Therefore
it is recommended to put the database files into a filesystem on a
disk connected by FCP/SCSI. For small systems, we recommend the
usage of ECKD raw devices, because this configuration needs less
CPU per transaction.
Test environment
IBM eServer zSeries 900 (2064-216)
IBM TotalStorage Enterprise Storage Server 2105-800
LPAR with 8 CPUs, 2GB memory
Novell/SUSE SLES 8 + SP2 for IBM zSeries (64-bit),
kernel 2.4.19
Informix 9.4.0 FC3 (64-bit)
Benchmark Informix OLTP
Database data Logical Volume (LV): 8 CHPIDs, 8 host
adapters, FCP/SCSI or FICON/ECKD disks in 8 ranks,
ext2 filesystem
For the usage of FCP/SCSI devices on SLES8 a kernel
level 2.4.21-251 or higher is recommended. This update
contains performance relevant fixes which improve the
throughput and reduce the CPU utilization to nearly
the same level as ECKD disks.
