SAND CDBMS Administration Guide
Installing and Configuring SAND CDBMS

System Configuration for SAND CDBMS Operation (UNIX)

Linux System Configuration

Follow the configuration suggestions in this section to improve SAND CDBMS performance on Linux servers (Red Hat or SuSE). All of the kernel parameters listed below are contained in the /etc/sysctl.conf file. Red Hat already provides this file, which is read at boot time. SuSE does not supply this file, so it will have to be created manually, and the system must be set up to read the file, either at boot time or via a crontab.

Changes to the /etc/sysctl.conf file can be made effective immediately by executing the following command:

sysctl -p

Red Hat Enterprise Linux 4 and SuSE Enterprise Linux 9 (2.6 Kernel)

PROCESSOR SUBSYSTEM OPTIONS:

Refer to the respective sections for Red Hat 4 and SuSE below.

SHARED MEMORY OPTIONS:

The following shared memory options are highly dependent on physical memory and should be set according to the subsequent table:

• kernel.shmall
• kernel.shmmax
• kernel.shmmni

Linux memory	kernel.shmall	kernel.shmmax	kernel.shmmni
2 GB	400000	1700000000	4096
4 GB	921600	3774873600	4096
8 GB	1971200	8074035200	4096
12 GB	3020800	12373196800	4096
16 GB	4070400	16672358400	4096
20 GB	5120000	20971520000	4096
24 GB	6169600	25270681600	4096
etc.	etc.	etc.	etc.

 

Red Hat Enterprise Linux 4 Only

PROCESSOR SUBSYSTEM OPTIONS:

kernel.shm-use-hugepages=1
vm.min_free_kbytes=4096
vm.nr_hugepages=10
vm.swappiness=60

 

SuSE Enterprise Linux 9 Only

NETWORK TUNING OPTIONS:

net.ipv4.conf.all.arp_announce=0
net.ipv4.conf.all.arp_ignore=0

PROCESSOR SUBSYSTEM OPTIONS:

kernel.mmap-hugepages-min-mapping=2048
kernel.mmap-use-hugepages=1
kernel.shm-use-hugepages=1
vm.min_free_kbytes=4096
vm.nr_hugepages=10
vm.swappiness=60

Note:
The vm.swappiness parameter relates to the 2.6 kernel only. The default vm.swappiness value is 60; this parameter can be set to 80 to enable faster swapping of pages. The optimal value will ultimately depend on the system; however, it should never be set to 100.