We have an application which runs in two distinct phases.  There is a
"loading" phase, characterised by a huge number (millions) of small
updates to rows to around 20 different tables, from around 10 - 20
concurrent clients.  There is also the "online" phase, which usually
has a small number of clients, executing complex queries operating
potentially over a large subset of the data.

We are running SAPdb 7.3.029 under RedHat 7.3, with the following
configuration.  The hardware and software details are provided below.
The system is running RAID (0+1) over 10 120GB drives.

What are the best practices for the two phases described above in
regards to RAID configuration, and the use of SAPdb devspaces?  Is it
better for SAPdb not to use RAID, and to allocate a separate devspace
to each separate drive and let SAPdb manage the parallelism itself?
The stripe size for the RAID is set to 64KB.


#setup parameters
param_startsession
param_init

param_put LOG_MODE DEMO
param_put LOG_IO_QUEUE 1000
param_put DATA_CACHE 120000
param_put CAT_CACHE_SUPPLY 20000
param_put MAXCPU 4
param_put MAXDATADEVSPACES 18
param_put MAXDATAPAGES 2024000
param_put MAXSERVERTASKS 24
param_put MAXUSERTASKS   200

param_put _LOCK_SUPPLY_BLOCK 5000
param_put  MAXLOCKS 15000
param_put  _ROW_RGNS 16
param_put  _TAB_RGNS 16

param_put  DEADLOCK_DETECTION 64
param_put  ROLLBACK_CACHE 256
param_put  _MULT_IO_BLOCK_CNT 64
param_put  _COPY_IO_BLOCK_CNT 64
param_put _IOPROCS_PER_DEV 4
param_put SESSION_TIMEOUT 0

param_checkall
param_commitsession

#define devspaces (tablespaces)
param_adddevspace 1 SYS system F
param_adddevspace 1 LOG /usr/sapdblog/itopixdblog1 F 50000

# 131072 = 1G

param_adddevspace 1 DATA idata1 F 262144
param_adddevspace 2 DATA idata2 F 262144
param_adddevspace 3 DATA idata3 F 262144
param_adddevspace 4 DATA idata4 F 262144
param_adddevspace 5 DATA idata5 F 262144

The machine specification is:

Vendor: Intel
Model: Xeon MP (Hyper-Threading capable)
Core Clock: 2.8GHz
Motherboard vendor: Supermicro
Motherboard model: X5DP8-G2
Motherboard chipset: Intel E7501 
No. of P64H2 Hub: 2
No. of PCI-X buses: 6
Front Side Bus: 533MHz
Memory Bus: PC1600/PC-200 (200MHz) DDR SDRAM
L2 Cache: 512K
SMP (no. of processors) 2 (hyper-threaded to 4)
RAM Total: 4GB
Type: DDR SDRAM Registered ECC
Speed: PC2100 (but only operate at PC1600)

Hard Disk Drive
Vendor: Western Digital
Model: WDC D1200JB-00CRA1 (Caviar Special Edition)
Size: 120GB x 10
RPM: 7200
Cache Size: 8MB
IDE Interface: Ultra ATA/100 (ATA-5)
Vendor: Seagate
Model: ST380021A
Size: 80GB x 2
RPM: 7200
Cache Size: 2MB
Interface: Ultra ATA/100 (ATA-5)

RAID Controller
Vendor: 3ware
Model: Escalade 7850 (7500-8)
PCI Bus: PCI, 64 bit/33MHz
Settings: Hardware RAID 10 (0+1)
Driver Name: 3w-xxxx 
Driver Version: 1.02.00.031
IDE Interface: Ultra ATA/133

Kernel Version: 2.4.20-neon-base
Swap Size: 2GB
GCC Version: 2.96
Glibc Version: 2.2.5-34
File System: Ext3