Today we're going to quickly discuss an amusing and terrifying cheatsheet about evil pratices about FreeNAS Storage and ZFS filesystems.

This is just my personal view but it's based upon a strengthened experience, so you're all invited to tell me what's yours.


ZFS has the ability to extend the ARC with one or more L2ARC devices, which provides the best benefit for random read workloads. These L2ARC devices should be faster and/or lower latency than the storage pool. Generally speaking this limits the useful choices to flash based devices. In very large pools the ability to have devices faster than the pool may be problematic. In smaller pools it may be tempting to use a spinning disk as a dedicated L2ARC device. Generally this will result in lower pool performance (and definitely capacity) than if it was just placed in the pool. There may be scenarios in lower memory systems where a single 15K SAS disk can improve the performance of a small pool of 5.4k or 7.2 drives, but this is not a typical case.

Monitoring is a key aspect of system administration. Looking inside a running server, obtaining some statistics or reconfiguring some aspects of an application are all daily administration tasks.

You always should monitor a Java application you deployed with Tomcat so here is a quick configuration cheatsheet about Tomcat 8.


What is preferred technique to connect to MySQL from within your bash scripts?

Some call mysql and other client utilities directly from within their bash scripts. Why? Because it's quick, easy and  straightforward.

Yes, a so simple and fundamental thing that is often treated as a detail. "I'll make it later..." or "I'll make it tomorrow, or someday..." - How many times did you say that? Let's be honest and keep track of the maintenance operations we need, so we can process them as a checklist.

Hi, I'm Giacomo Arru and I'm the System Administrator at BETA Technologies. Managing datacenters requires constant studying and every experience is important and precious. Today I'll share some useful tips and considerations about the Virtualization Storage under Citrix XenServer and FreeNAS.


Here are 5 quick tips you should keep in mind while designing ZFS Storage for Virtualization use with Citrix XenServer (but it should be fine also with VmWare).