Since version 11 came out, there have been three updates - what SUSE calls service packs - in June 2010, February 2012 and January 2013.

One major change is the introduction of systemd as the default init system. However, SUSE has chosen not to include journald, the new system logging method.

Matthias Eckermann, senior product manager at SUSE, told iTWire in response to a query: "We have done a thorough review of all INIT systems about three years ago. Despite the negative sentiment in the open source community, our evaluation back then has shown that systemd is the most promising approach going forward."

Red Hat employee Lennart Poettering is the main developer behind systemd which has come in for criticism because of the fact that it tries to do too much. It has merged udev, does logging; has substitutes for ntpd, cron, automount, inetd, and network configuration and recently a console daemon was announced to replace the kernel's virtual terminals.

Eckermann said that SUSE supported the idea that the UNIX approach of "one tool for one use case" was a scalable approach, "and thus we understand that people are sceptical about systemd".

"Thus we have taken specific measures to make systemd 'acceptable' for a majority of people, specifically those coming from traditional UNIX and Linux. To name three parts of our approach:

"A backward compatibility layer which includes the command line. For example, an administrator can continue to restart "sshd" using "rcsshd restart", and while   doing so, he will learn how to do this in system natively going forward.

"Testing that LSB-compatible init-scripts continue to work.

"We are not using all systemd features, most obviously we are using 'rsyslog' as the system syslog daemon, not systemd's journald."

Asked about the new rollback feature in SLES 12 which works with Btrfs, Eckermann said for new installations, the _default_ filesystem for the operating system would be Btrfs. "Thus all customers by default get the rollback functionality. A customer can chose other filesystems (xfs, ext-family) for the OS as well, but won't get the rollback functionality."

He said that for data partitions and applications the default filesystem would be xfs, as there were known performance penalties for the Copy-on-Write functionality (this applies to all filesystems based on CoW, not only btrfs!) for example when storing large database files or VM images. "As we do not want customers to run into this unexpectedly, we are setting the default for data and applications to "xfs" (which we do support for 12 years already)."

Eckermann said there were good reasons why a customer might chose Btrfs for data - which was supported as well.
 
For example, "The integration of Samba 4.x with btrfs (Server-side-copy) and snapper (FSRVP) and using btrfs for /home/<User> in combination with pam_snapper".

SLES 12 also has the ability to patch a running kernel using kGraft, a kernel module that SUSE announced in February.

Eckermann said the release had this technology included in the kernel.

"However, obviously this needs KMPs (kernel module packages) to be produced, tested and delivered, which (the KMPs) then contain the kernel live patches (applied as a kernel module).

"Those KMPs will be delivered by SUSE as a separate subscription/service starting a 'bit later' than now."

The KMPs are likely to be ready by the time the company holds its annual conference, SUSECon, in Orlando, Florida, in mid-November.

Other features in the release are full support for the open source database system MariaDB - which replaced MySQL - support for the open-vm-tools together with VMware for better integration into VMware-based hypervisor environments, and integration of Linux containers into the virtualisation management infrastructure (lib-virt).

Additionally, Docker is provided as a technology preview and there is support for the 64-bit Little-Endian variant of IBM's POWER architecture, and continued support for the Intel 64/AMD64 and IBM System Z architectures.