Memory fragmentation can happen in any operating system, but if you are running a memory intensive workload like SAP HANA, fragmentation can put an upper limit on how long the application can be available before needing to be restarted.
Increasing the amount of virtual address space can alleviate this problem by providing more memory to the application.
SUSE increased the virtual address space available in SLES 12 Service Pack 3 for POWER to 512TB last year to help with this problem.
Unfortunately, many of our SAP HANA customers on POWER started out on SLES 11 SP4 and will be running on SLES 11 for a long time to come. What about them?
Help has arrived: with the kernel-bigmem–3.0.101-108.7.1 update, we now support up to 128TB virtual address space on SLES 11 SP4. This provides the head room to allow customers to run their memory intensive applications, like SAP HANA, for longer periods between restarts.
This capability complements the support for 32TB of physical memory that was introduced with the bigmem kernel about a year ago (Blog: More memory now available for SAP HANA on SLES 11).
For more information, please see the SUSE TID at https://www.suse.com/support/kb/doc/?id=7018408