USB 3 Hard Drive Enclosure TR8U+

[HardwareTerrorz]

TowerRAID TR8U+ 8-Bay SATA to USB 3.0 JBOD

Is this unit compatible with MacZFS? Western Digital is supposedly coming out with 4TB and 5TB Red drives (their NAS drive is named WD Red). I'm thinking of getting some of them, putting them into one of these TR8U+ towers, and connecting the USB 3 to the back of a (USB 3 model) Mac Mini.

So, the internal drive would have the latest Mac OS on it and this TowerRAID would have 8 hard drives in JBOD mode connected to it. And since there are 4 USB ports on the Mini, I could even plug in 3 more towers and expand out my RAID-Z3 storage. Does that sound like an easy thing to do? It does to me, but I don't have a ZFS system yet.

[Bjoern Kahl]

Am 14.03.13 19:05, schrieb HardwareTerrorz:

In principle, yes should work.

Just make sure this Tower RAID has a true JBOD mode, i.e. it simply
presents the drives 1-by-1 to the host. Some RAID systems lie and
still write some RAID meta data to the drives and mess around with the
read/write request. Makes data recovery in case of hardware failure
difficult.

Also keep in mind, these are USB enclosures. We have had several
reports about bad USB controllers lying about write barriers and cache
management. A deadly threat for a transactional file system like ZFS.

See http://www.maczfs.org/wiki/USB


Best regards

Björn

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[X Bytor]

On Thu, Mar 14, 2013 at 1:05 PM, HardwareTerrorz <hardwar...@gmail.com> wrote:

TowerRAID TR8U+ 8-Bay SATA to USB 3.0 JBOD

USB and USB2 are considered unsuitable for use with ZFS. I don't know if USB3 or this enclosure has addressed the underlying technical issues.

-X

[Jason]

What he said. In spades.

Jason
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[HardwareTerrorz]

http://www.sansdigital.com/towerraid-/tr8uplus.html

I think I'll ask SD for some support on the topic. If I can get a conversation with a L3 tech, I might be able to answer those questions. I hope so anyway. It's a cheap enclosure, for what it is.

Thanks!

[Daniel Becker]

On Mar 14, 2013, at 11:05 AM, HardwareTerrorz <hardwar...@gmail.com> wrote:

> And since there are 4 USB ports on the Mini, I could even plug in 3 more towers and expand out my RAID-Z3 storage.

I don't think MacZFS actually supports triple-parity RAIDZ. (And even if it does, you would most likely be much better off with a pool of four mirrors.)

[Lucien Pullen]

Also sprach Daniel Becker at 3/14/13 2:35 PM:

> On Mar 14, 2013, at 11:05 AM, HardwareTerrorz <hardwar...@gmail.com> wrote:
>
>> And since there are 4 USB ports on the Mini, I could even plug in 3 more towers and expand out my RAID-Z3 storage.
>
> I don't think MacZFS actually supports triple-parity RAIDZ.

I've checked. It does not unless I seriously misunderstood the
code. RAIDZ1 and RAIDZ2 are your options.

[T]

Well that stinks. I thought a full ZFS implementation meant that I would be able to choose the level of parity...

[Lucien Pullen]

Also sprach T at 3/14/13 2:44 PM:

> Well that stinks. I thought a full ZFS implementation meant that I would be able to choose the level of parity...

RAIDZ3 was implemented at a later revision. MacZFS is v8. Basically
everything (read: not sharenfs or .zfs mounting) is implemented from
that.

[T]

Just to follow up, here is the response that I got from San Digital:

"TR8U+ does present the drives one by one to your host computer. It doesn't write any meta data to drives in order to JBOD mode.

We believe it should be ok to use it with ZFS system. However, since we don't have ZFS system to test and don't have other customers have the same application, we are unable to verify it."

[Boyd Waters]

I've had good results with the Addonics Mini Storage Towers, using a SATA Port Multiplier connected with a Silicon Image 3132 PCIe eSATA card in my old Mac Pro. This was perhaps 4 years ago, back when dinosaurs ruled the Earth and MacZFS came from Apple...

This combination worked well enough for light loads in a RAIDZ1 configuration with 4 drives.

The internal arrangement of the internal SATA cables in the Addonics Mini Tower wasn't all that great, but airflow was OK.

http://www.addonics.com/products/mst.php

A less-expensive option is the Sans Digital enclosure, which uses a simple SATA backplane. Not as much airflow, but I had decent results with it.

http://www.newegg.com/Product/Product.aspx?Item=N82E16816111177

I also used these towers on a PC with Linux and Solaris 11 Express.

The eSATA Port Multiplier slows things down to a single SATA I interface, but that's OK because the cheap Sil3132 host bus adapters can't keep up with much beyond that anyway.

http://www.newegg.com/Product/Product.aspx?Item=N82E16816124004

Again this was long, long ago.

I try to avoid USB 2. Good FireWire enclosures are getting expensive. USB 3 is (on paper) a significant upgrade: not only faster but also the USB 3 spec assumes an intelligent controller (like USB OTG) and over-the-wire protocol more closely resembles SATA. But I don't have any USB 3 hardware at the moment.

[Fastmail Jason]

Yes Addonics are very good. I build custom boxes, but love Addonics boards with 5 SATAports.

--

Jason Belec

Sent from my iPad

[Daniel Becker]

On Mar 15, 2013, at 1:45 PM, Boyd Waters <water...@gmail.com> wrote:

> The eSATA Port Multiplier slows things down to a single SATA I interface, but that's OK because the cheap Sil3132 host bus adapters can't keep up with much beyond that anyway.

Is this a limitation of the SiI3132 chipset and/or the particular PMP you're using? In principle, you should be able to talk to drives at SATA-2 rates even through a multiplier (although you'll want a controller that supports FIS to actually get decent performance).

[Daniel Becker]

On Mar 15, 2013, at 3:31 PM, Daniel Becker <razz...@gmail.com> wrote:

> (although you'll want a controller that supports FIS to actually get decent performance).

And on that same note, if you do end up going the USB3 route, make sure both your controller and your enclosure support UAS, not just plain old BOT.

[Fastmail Jason]

Depending on the system, hardware, etc., you can get some pretty amazing speeds. Connecting Addonics 5port SATA board through ESATA to a Sonnet Tech board via Thunerbolt provides stunning speeds. seems Sonnet drivers may be the key for SIL3132.

--
Jason Belec
Sent from my iPad