jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

jclulow

So, to get something like /etc/rc.local you can use the custom SMF import facility. (See the source for more information about how this actually works.)

/opt is mounted out of zones/opt by default. You can create a directory /opt/custom/smf and populate it with SMF manifests. Any manifests you put in there will be imported by SmartOS when it boots. Below is an example SMF manifest that simply starts /opt/custom/bin/postboot, a self-explanatory shell script that you can use like /etc/rc.local.

Note that it would likely be better to customise and respin your own images, as putting a bunch of platform state in the zones pool undoes some of the benefits of the ramdisk platform architecture that SmartOS has.