Tech Info 106: Solaris 10 ZFS problems with database applications

HELIOS Tech Info #106

Tue, 20 Feb 2007

Solaris 10 ZFS problems with database applications

We have tested Solaris 10 release 11/06 with ZFS without any problems using all HELIOS UB based products, including very high load tests. 
However, we learned from customers that some database solutions (known are Sybase and Oracle), when allocating a large amount of memory may slow down or even freeze the system for up to a minute. This can result in RPC timeout messages and service interrupts for HELIOS processes. ZFS is basically using most memory for file caching. Freeing this ZFS memory for the database memory allocation can result into serious delays. This does not occur when using HELIOS products only.
The HELIOS tested system was using 4 GB of memory.
The customer production machine was using 16 GB of memory.
Contact your Sun representative how to limit the ZFS cache and what else to consider using ZFS in your workflow.
Check also with your application vendor for recommendations using ZFS with their applications.