FreeNAS in Production

I work as a Network Administrator in a shop where we deploy 60+ ESXi VMs on a half dozen host servers.  We heard about FreeNAS from my predecessor who implemented it where he is now employed.  My boss asked me to evaluate FreeNAS as it is time to replace one of our existing SANs.  I installed FreeNAS 9.3 on an old IBM server and took the four 3-hour FreeNAS classes from Linda Kateley. I then dove in head first with a new 4U SuperMicro SAN with dual Intel CPUs, 128GB EEC RAM, twenty 4TB SAS HDDs and a handful of consumer grade SSDs.  The important lessons learned are:

  1. Buy big RAM chips so you have available slots if you need more RAM.
  2. eMLC SSDs cost more but they are definitely better than off the shelf SSDs.
  3. There is a 4X & 5X FreeNAS rule that states you want 4 or 5 times as many gigabytes of SSD capacity for cache as you have gigabytes of RAM.  I always go big so we deployed the 8X rule.
  4. Download FreeNAS and install it on a test platform and then take Linda Kateley’s four paid and one free interactive online class to get started.  The FreeNAS forum is wonderful as long as you research your questions before posting.
  5. RAID cards are not needed but if you want an LSI RAID card make sure you flash it to IT (pass through mode).  LSI support & the FreeNAS forum were great in guiding me to the correct utilities I needed for my LSI SAS 9211-8i Host Bus Adapter.
  6. If you want the lights to work correctly on the front of a SuperMicro SAN use only SAS HDDs.

A very knowledgeable admin on the FreeNAS forum sent me a quote that is quite appropriate:  “It’s like a learning cliff.  We know.”  That said, Linda’s class made it much more like a steep hill and very manageable.
Currently I have the fastest SAN I have ever had the pleasure of working with and all the hard work pays off when you see you have maxed out your state of the art fiber gigabit network.

Dale Josephson
Network Administrator
Karuk Tribe

2 Comments

  1. Mike

    I thought that FreeNAS does not have caching as a ‘feature’? Do you have a whitepaper or some sort of detailed write up of what you did? If I can cache or tier with FreeNAS I’d be more than happy to contribute to the project. I’m interested in using my own hardware… essentially, I’d like TrueNAS features but the freedom to use whatever hardware I’d like… any comments would be appreciated. Thanks!

    Reply
    • jkh

      Not sure what you mean by “caching” in your question. FreeNAS certainly supports ARC and L2ARC caches as well as a write cache (ZIL) device, and all of these are well-documented features of ZFS.

      Reply

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