This post is a follow-up to the article how to install Solaris 11.2 with Unified Archives. As explained in a former post I think the combination of Golden Images and Puppet makes a lot of sense. But what is the best or easiest method to install and configure the Puppet agent on a newly deployed server? This post shows an easy way for Solaris 11.2.
Solaris 11.2 released
After a short public beta phase, Oracle made Solaris 11.2 generally available last week. You can download it from oracle.com in various forms like the usual install ISO, Unified Archives and as Virtual box appliance.
There are many, many new features, but also a lot of small incremental improvements.
Some of the new key features are:
- Openstack
- Kernel zones
- Puppet
- Unified Archives
- Elastic Virtual Switch
Control the size of the ZFS ARC cache dynamically
Last updated on: 25th Dec 2014
Solaris 11.2 deprecates the zfs_arc_max kernel parameter in favor of user_reserve_hint_pct and that’s cool.
tl;dr
ZFS has a very smart cache, the so called ARC (Adaptive replacement cache). In general the ARC consumes as much memory as it is available, it also takes care that it frees up memory if other applications need more.
In theory, this works very good, ZFS just uses available memory to speed up slow disk I/O. But it also has some side effects, if the ARC consumed almost all unused memory. Applications which request more memory need to wait, until the ARC frees up memory. For example, if you restart a big database, the startup is maybe significantly delayed, because the ARC could have used the free memory from the database shutdown in the meantime already. Additionally this database would likely request large memory pages, if ARC uses just some free segments, the memory gets easily fragmented.