FreeNAS performance and question aboout plex server

[Alexandru Gavrilescu]

Hi guys, My name is Alex, I am new to Freenas and I have a few questions that maybe you can answer.

I am running FreeNAS-11.0-RC3 (1d8ee7925) as a VM (ESXi 6.0.0 A-02).

My system is a Dell Poweredge T710 with the following specs:

CPU: 1 X Intel Xeon E5645 @ 2.4 Ghz (6 cores, 12 threads) - I already ordered the second CPU
RAM: 24 Gb (6 X 4Gb SAMSUNG DDR3 PC3-10600R DDR3-1333MHz ECC RAM) - I already ordered another 6 X 4 Gb sticks.
HDD: 8 Tb in RAID-Z2 (4 X 2 Tb Hitachi UltraStar 0F10452 7,2k HUA722020ALA330 Enterprise-Class EMC DELL)
146 Gb (2 X 73,4 Gb Seagate Cheetah 15K RPM, SAS, 3Gb/s HDD, 16MB ST373455SS DELL)
NETWORK: Dual embedded Broadcom NetXtrem II 5709c Gigabit Ethernet NIC
RAID: PERC H200i Flashed with LSI-9211-8i firmware for passthrough.

I must add that the resources allocated to the Freenas VM are:
CPU: 4 Cores (2 cores x 2 thread)
RAM: 12 Gb

Initially I had the 8 Tb hdd in a RAID-Z2 and created 3 SMB shares: Media, Documents and Various, I have noticed that when I copy from one share to another sometimes the copy speed is good (70 to 100 MB/s) but sometimes it is very very slow (7 to 10 MB/s) also this applies to when I copy from Freenas to my laptop or my desktop pc, so I decided to use the other 2 SAS HDD to use them as cache, so I think I have done something stupid, I put these in RAID 1 and I extended the previous volume with these 2 SAS HDD as Cache and hence my first question, did I do something stupid?

Also I would like to ask, i noticed the drop in read/write speed mostly when my kids are watching cartoons from Plex on the TV. The movies are 1080p and the Plex server is hosted as a jail in freenas. My question is could this be the reason for my drop in speed?

Is there something in my hardware configuration that is not good or are there some tweaks in Freenas that I can use to improve my read/write speeds?

Thanks

 

[Vito Reiter]

Your initial problem probably lies within the fact that FreeNAS is running as a VM which is going to perform worse than a bare metal install, if there's only one 1080p stream then it shouldn't affect the performance too much, but you can dim it down to 720p and test accordingly. As for the cache setup, I don't think it's a good idea to even set that up let alone with hard drives and not flash storage. You have more than enough RAM to cover that. Also, transfers speeds to your local systems are going to depend on the speed of those as well. You can't expect to write to a 5400RPM laptop drive at 100MB/s (I know you didn't specify hardware in the LAN systems but just an example.) Also, are performance drops specifically when there is streaming or is it in general?