Suggestions to increase performance with SSD or USB 3.0 Flash drive

[NAScake]

Howdy,

First time poster and FN Newb. Love it, learning, hope I can contribute to the forum at some point.

I've got a little AMD E350IA board & 8GB of RAM powering my NAS. Running 8.0.4 from a 4GB USB 2.0 flash drive. I'm looking for info on performance boosts by using an SSD or a USB 3.0 flash drive for cache. I've read that SSD is the way to go but since my board supports USB 3.0 I thought I would see if anyone has attempted it. Also, with using either for cache what is the ceiling for size? Does it incrementally help with performance the larger your drive gets? Or is there a max? I've got a 60GB Sata III on the way but plan to build a few more of these and would like to push the hardware to perform.

Thanks!

~NC

 

[Joshua Parker Ruehlig]

Howdy,

First time poster and FN Newb. Love it, learning, hope I can contribute to the forum at some point.

I've got a little AMD E350IA board & 8GB of RAM powering my NAS. Running 8.0.4 from a 4GB USB 2.0 flash drive. I'm looking for info on performance boosts by using an SSD or a USB 3.0 flash drive for cache. I've read that SSD is the way to go but since my board supports USB 3.0 I thought I would see if anyone has attempted it. Also, with using either for cache what is the ceiling for size? Does it incrementally help with performance the larger your drive gets? Or is there a max? I've got a 60GB Sata III on the way but plan to build a few more of these and would like to push the hardware to perform.

Thanks!

~NC

You want to run the arc_summary script to benchmark usage. There's an article somewhere that explains what to look for too see if you actually need more caching (if zfs is throwing stuff out of arc_cache soon before it is used). It needs perl so you need to install that on your FreeNAS system.

 

[ProtoSD]

The arc scripts have been converted to Python and are included in 8.0.4 and later. They need to be run from the command line. The documentation is a good place to start:

http://doc.freenas.org/index.php/Arcstat

 

[paleoN]

It's always better to add more RAM if you're not maxed out, which you are. Some additional reading about cache drives if you do need one:

ZFS Best Practices Cache Devices

[post=20557]TECK's build post #10[/post]

 

[NAScake]

Thanks for all of the info.

I actually have about 20 16 drive short 3U rackmount storage chassis I'm converting to FreeNAS systems for clients or whomever wants them. I've been in IT for a while but mostly the MS world so this is my entry into BSD and linux. I started with that E350 board and thought it would be good for low traffic and a small amount of drives. I have my eye on a few server rated mini ITX boards that support 16GB so that will be my next build to test. I've been getting rocketraid 2340's and so far they work well.

I've got some reading to do thanks to you guys. Is the ability to cache on another drive specific to pools or is it a system wide thing?

Thanks!

~NC

 

[paleoN]

I've got some reading to do thanks to you guys. Is the ability to cache on another drive specific to pools or is it a system wide thing?

It's per pool.

For some workloads, e.g NFS heavy or database, a log device is probably more important. You would need to have it mirrored though as it's a single point of failure.

 

[NAScake]

Thanks paleoN I've read that is important as well.

Thanks again all.

~NC