Slow Write Speeds

[ggjono]

Hi there, I am new to these forums so apologies if I miss something out or i've posted this in the wrong place.

I'm currently running Free nas 9.3 on a Hp Microserver gen8 Via ESXI with 8GB of assigned Ram, 2 old 500gb hard drives and 2 new 3TB WD Green drives over a cat5e/6 network.

After setting it up, I seem to be seeing bouncing transfer speeds on my new 3TB disks from 60/70MB's down to 10MB's a majority of the time or even a stand of 0MB's still for periods of time. The performance seems to worsen when the two disks are grouped together and mirrored.
When reading from the disks they seem to hover around 30MB's.
Cpu useage doesn't seem to go above 60%, Disks seem to stay around 20MB's on write and 30MB's and memory usage stays around 6GB according to the reporting.
For extra information I am running this without any of the hardware or software raid settings set and using windows shares accessed via a windows 8 machine.

I was wondering if anyone had any ideas where I might have gone wrong, I am a noob to working with servers however

 

[tvsjr]

It's pretty well documented here that virtualizing FreeNAS is a Bad Idea. It can be done, but there are many more issues you need to deal with to get it to perform decently. Are you passing an HBA through to the FreeNAS VM via VT-D, or have you just created VMDKs on each drive and passed those through?

In short... if you're a n00b, starting out your virtualization experience with something that is very dependent on low-level hardware access and that places a massive IO load on a system isn't a great idea.

 

[ggjono]

Okay, So I am guessing the best bet for me right now is to test it on bare metal and see if that improves the performance.
My initial idea behind the virtualization was so I could add on PFSense once FreeNas has settled however due to the memory requirements of FreeNas I won't be able to that sadly.

 

[tvsjr]

And keep in mind that 8GB is the bare minimum required. 16 or even 32 are typically recommended, and some of us run far more than that. Someone around here has 1.5TB of memory...

Firewalls are something else that doesn't run well in an oversubscribed virtual environment. You'll see weird behavior, random high ping latencies/packet loss, etc. Pick up a nice low-power "appliance sized" PC, or a little 1U low-power box if you're putting this in a rack, and run pfSense there. Virtualization is great, but it's not always the answer.

 

[jgreco]

Actually you may be able to fix firewall performance by reserving capacity for the firewall, but, yeah, generally speaking, in a hypervisor environment you want to make sure your hypervisors have plenty of elbow room.

 

[ggjono]

You guys have a point thanks for the help! I knew I'd be hard pushed to get it to work but as you said high pings and just in general poor performance isn't really worth it for the protection against the occasional thing in a home environment.

 

[tvsjr]

Well, you should definitely have a firewall appliance in place. Your average home "gateway" device isn't worth much of anything. However, doing it as a VM isn't the greatest solution. I tried it myself... despite having some fairly significant VMware experience, I still couldn't make it behave as well as a physical device.

pfSense is very light-weight in most home use cases, so don't let not being able to virtualize it easily discourage you. There are plenty of $50 small form factor PCs on eBay that would do a great job. Since I have a rack at the new house, I picked up a nice Supermicro 1U box off eBay for $200 - quad core E3, 16GB RAM, quad NICs on board, idles along at about 40 watts. It's more than sufficient for my use case (~10 VLANs, 50/8 Internet connection, running pfSense, Snort, etc.)

 

[ggjono]

Yeah I want it in but as a student with limited budget and space its a bit difficult to justify. That's why I ended up with the Microserver as I knew it was small and reasonably quiet. But it's something I might consider in the future.