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backporting XHCI fixes from freebsd 9.x (r243780)

Western Digital Drives - The Preferred Drives of FreeNAS and TrueNAS CORE
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diablodale

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Is there any precedent in FreeNAS backporting a fix/feature update from a future BSD version into a current FreeNAS nanobsd build?

I am interested in the XHCI update which adds support for the Etron series of USB 3.0 controllers.
http://freshbsd.org/commit/freebsd/r243780

--Dale
 

cyberjock

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FreeNAS supports many USB3 controllers. It is not enabled by default however. If you consult the manual it explains how to enable USB3 and why it is not enabled by default.

Edit: Not sure if it supports the exact controller you are asking about, just providing advice for you to look it up.

Overall, there's no gain from using USB3 in the big scheme of things. Bootup and shutdown times are not changed and you really shouldn't be using USB devices at all on FreeNAS as regular use. It's only really recommended when you are first copying data to your server during initial setup.
 
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diablodale

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I would like to use two USB 3 sticks as an L2arc. From my reading, it can be a very good low cost solution to speed reads on my ZFS based freenas. Have you read or experienced otherwise?

From my searching on that controller, only the commit I linked added support for it. Prior freebsd versions are not successful in initializing the controller. There was a handshake which the prior code didn't fully implemented that was needed.
 

cyberjock

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I wouldn't recommend it. You'll kill the USB stick in no time. USB uses alot of interrupts but more importantly has no protection against uneven wear of the drive. Not to mention L2ARC doesn't really provide much benefit except in extremely high workload environments.
 
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diablodale

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Will you promise that the stick shoots flames out the side?! Oh please...I like a good fireworks show. ;-)

I don't mind the experimentation. As I was researching, the L2ARC is read heavy, not write heavy. In contrast, the ZIL is write heavy and it is highly suggested to use only enterprise-level SSDs or battery-based RAM disks for it due to the extreme write needs and rare reads.

Thanks for your insight. As I understand, the freenas team does not often backport features from a newer generation of freebsd; preferring to keep with the codebase shipped with the base freebsd distrib.
 

cyberjock

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LOL @ the fireworks.

Actually, it's a little of both. There's a thread that's pretty recent where L2ARC deep level stuff is discussed. Pretty much unless you are in a situation where your hard drives are being accessed constantly by multiple users(in effect causing the drives to be in a continuous condition of always reading and/or writing the L2ARC is pointless. All you would potentially save from an idle zpool is a few ms of seek time which nobody would ever notice.

Pretty much the same is true for the ZIL. It only appears to cache writes smaller than 64k that are sync writes, which pretty much excludes just about everything except database-type situations and iscsi in certain situations.
 
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