1. Doufám že máš v tom serveru hodně RAM, na ZFS se doporučuje minimálně 8GB RAM. Ten filesystém je skvělý, ale má krvavé nároky a nemyslím si, že dokážeš využít jeho vlastností.
Na RaidZ potřebuješ alespoň 3 disky, jedná se o ekvivalent RAID5 nebo 6 (Z1 nebo Z2).RAM
The best way to get the most out of your FreeNAS™ system is to install as much RAM as possible. If your RAM is limited, consider using UFS until you can afford better hardware. ZFS typically requires a minimum of 6 GB of RAM in order to provide good performance; in practical terms (what you can actually install), this means that the minimum is really 8 GB. The more RAM, the better the performance, and the Forums provide anecdotal evidence from users on how much performance is gained by adding more RAM. For systems with large disk capacity (greater than 6 TB), a general rule of thumb is 1GB of RAM for every 1TB of storage.
NOTE: by default, ZFS disables pre-fetching (caching) for systems containing less than 4 GB of usable RAM. Not using pre-fetching can greatly reduce performance. 4 GB of usable RAM is not the same thing as 4 GB installed RAM as the operating system resides in RAM. This means that the practical pre-fetching threshold is 6 GB, or 8 GB of installed RAM. You can still use ZFS with less RAM, but performance will be affected.
If you use Active Directory with FreeNAS™, add an additional 2 GB of RAM for winbind's internal cache.
If you are installing FreeNAS™ on a headless system, disable the shared memory settings for the video card in the BIOS.
ad 2. Shadow Copy je totéž co ve Windows - umožňují udělat snímek souborů na disku k určitému datu a případně se k takovým datům řízeně vracet (tj. např. můžeš mít 6 verzí jednoho souboru, tak jak šly jednotlivé snapshoty za sebou)
ACL je pak akronym pro ACcess List. Tj. rozšíření standardního unixového systému práv 3xRWX (owner-group-everyone) na vícečetný a granulárnější seznam (á-la Windows).
edit: viz http://doc.freenas.org/index.php/Hardware_Requirem ents