Problem with AFP transfer speed

[Hans Baumeister]

I'm having some severe issues with transfers from an external harddrive on my Mac (connected by Firewire) via Gigabit LAN to my FreeNAS. The NAS HW should be quite performant: dual core 2.2 GHz, 16 GB RAM, 4x WD Red 3TB drives.

I've had transfers up to 50MB/s quite consistently. It seems, however, that the more I copy onto the NAS, the slower transfers get. I've got one transfer going that Pathfinder is currently clocking at 2.7MB/s (it started at 13!) and another transfer via ChronoSync which has only been able to transfer about 420MB in the last 4 hours. Unfortunately, ChronoSync doesn't show the average throughput, but when I tried to transfer these files (they are Aperture libraries) using Pathfinder, it gave me a throughput of around 130kB/s (yes, KILObytes!).

Unfortunately, I am unable to figure out if the slow speed is due to an issue on my Mac (though I haven't had any speed issues with this external drive before) or if it is something to do with the NAS. The NAS isn't showing much disk activity (it shouldn't, at this slow transfer speed!), system load avg. on the 15 min. scale is around 0.2.

Anyone have this issue before? I need to solve this, or I'll be transferring files for the next month!

Thank you!

 

[cyberjock]

Can you elaborate a few things..

What CPU in particular? There's Atoms that do 2.2Ghz and they'll give crap for performance(but not necessarily as bad as what you are seeing). ;) More specs such as motherboard might be useful too.

What protocol are you using?

Are you going over wifi or using one of those powerline adapters?

I'd try to do some speed tests of your external drive as a first test. External drives don't always allow for SMART testing and monitoring. So when a drive starts failing you'll have no way to know ahead of time except that performance will be horrible due to the excessive error rates and time spent in error recovery mode.

 

[Hans Baumeister]

Okay, here is a bit more information:

FreeNAS System:
CPU: AMD Turion(tm) II Neo N54L Dual-Core Processor
RAM: 16GB ECC
Build: FreeNAS-9.2.1.1-RELEASE-x64 (0da7233)
Connected via Ethernet (Gigabit) via TP-LINK TL-SG2216 Gigabit switch
Using AFP shares to copy information (should I switch to CIFS instead?).

The really odd thing is that I've transferred from that same external drive just yesterday with around 50MBit/s...

Also, the transfer sped up later that evening (night). Again, Chronosync doesn't provide throughput averages, but I was seeing megabytes being transferred at each update, so things perhaps got back to regular speed (or something close to it).

Even though the CPU load and especially the disk throughput is really low even now (while transferring data), I hear spurts of activity on the box that I can't place. Nothing in the console looks that suspicious, except that I'm getting periodic AFP logouts and log-back-ins (about once per hour), but no error messages. The console sais I'm using AFP 3.3, by the way...

 

[cyberjock]

I don't have any recommendations. I know that CPU isn't going to set any speed records. It's almost as bad as an Atom in the performance arena. You could try CIFS. Not sure if its going to make a difference or not...

 

[Hans Baumeister]

I don't have any recommendations. I know that CPU isn't going to set any speed records. It's almost as bad as an Atom in the performance arena. You could try CIFS. Not sure if its going to make a difference or not...

Honestly, I doubt it is the CPU. It never goes over 20% throughout all of this, the 15 min. load average is 0.23.

I'm guessing it is either my Mac (I have weird stuff going on that can't possibly all be due to Mavericks) or my Switch.

 

[cyberjock]

Honestly, I doubt it is the CPU. It never goes over 20% throughout all of this, the 15 min. load average is 0.23.

I'm guessing it is either my Mac (I have weird stuff going on that can't possibly all be due to Mavericks) or my Switch.

That's fine. From my 2 years here I've learned one thing.. the second someone talks about poor performance with embedded CPUs(which yours is), its time to explain that they didn't buy a powerhouse of a processor. Embedded CPUs are never ever high-performance CPUs. For that reason I avoid them out of hand. They might work okay for NFS since NFS is very low in terms of CPU usage, but few people use NFS.

I also avoid AFP out of hand because of how many problems people have, and how few people actually use AFP. Being on an island by yourself when you have a problem is never a good place to be. There's lots of "AFP has problems" threads, and basically all of us experienced guys just ignore those threads because none of us are Apple users and we like protocols that work across many platforms(which CIFS and NFS do).

 

[Hans Baumeister]

That's fine. From my 2 years here I've learned one thing.. the second someone talks about poor performance with embedded CPUs(which yours is), its time to explain that they didn't buy a powerhouse of a processor. Embedded CPUs are never ever high-performance CPUs. For that reason I avoid them out of hand. They might work okay for NFS since NFS is very low in terms of CPU usage, but few people use NFS.

I also avoid AFP out of hand because of how many problems people have, and how few people actually use AFP. Being on an island by yourself when you have a problem is never a good place to be. There's lots of "AFP has problems" threads, and basically all of us experienced guys just ignore those threads because none of us are Apple users and we like protocols that work across many platforms(which CIFS and NFS do).

I'm confused: isn't the load average and cpu utilization, both very low while this is going on, an indication that the CPU can keep up with what is asked of it? Agreed that this CPU isn't an 8-core power monster, but then, I'm not looking to render a 3-d version of some animated movie... again, the reporting results are telling me that the CPU isn't overloaded...

As for AFP - it's disconcerting to hear that there are AFP issues, but I have no issue switching to NFS or CIFS. I'm having some issues getting these to work with the Mac but I'll post that separately.

Thanks again.

 

[cyberjock]

Well, if CPU usage is 23%, and you have a CPU with 4 cores, you are basically maxing out 1 core. Also, because of how close to 25% it is, its also very likely you are using a process that is single threaded. For example, CIFS is very very sensitive to CPU frequency because CIFS is single threaded. CIFS is also extremely CPU intensive as a protocol, so it really taxes CPUs more than others like NFS. And since 90%+ of users use CIFS, guess what their chief complaint is when they use a 1.6Ghz Intel Atom? ;) This is one reason why we often recommend Pentium CPUs like the g2020. It may only have 2 cores/2 threads, but it goes to 2.9Ghz, and for less than $70 it's really hard to get a CPU with that speed

On my E3-1230v2 CPU I can max CIFS out at about 250MB/sec on my system with 10Gb LAN. With NFS on the same hardware(which is multi-threaded and very very low in CPU usage) I go over 600MB/sec. The bottleneck is actually my SSD on my desktop and my pool performance at that point.. haha.

Just as a comparison, check out your CPU against my 4 year old laptop CPU. Mine's about 2.5x more powerful.. and its four years old! Hopefully this clears up why I said earlier in this thread that as soon as I hear someone complain about performance with an embedded CPU I knows its time to explain that they didn't buy a powerhouse of a processor. Because they bought a CPU that isn't a powerhouse and just flat out isn't a good choice for a server if "performance" as a consideration. Embedded CPUs are engineered to be extremely low power, low maintenance situations where the load will be extremely low to non-existent and fairly constant through the system's life. That's really not the situation you are in and that's not indicative of the loading FreeNAS has.

 

[Hans Baumeister]

I guess I need to upgrade to 10GBit Ethernet

This is interesting: I've basically swapped out my Mac Mini (with which I had these issues) with my MacBook. Since it has a firewire 800 connector, I attached the external disk to it via that (it was connected to the Mac Mini in the same way).

For quite some time, transfers got consistent 25 MB/s, but all of a sudden (after hours) performance is variable again. Down to kB/s, back up to 25, rollercoaster. What a pain.