Well, almost a year later now, and I need more space. WD still haven't released a 4TB "Green" drive yet (roadmap says 2013Q3, sometime in the summer), and the Black ones are too hot, noisy, and expensive.

So.. I discovered that Seagate, having abandoned "Green" drives, have actually come out with a new 4TB model. They call it a "Desktop" drive rather than a "Green" drive, but it spins cool/quiet at 5900rpm just like the earlier Seagate "Green" series did.

I'm wary of Seagate from an incredible string of past (3-4 years ago) firmware and mechanical failures, but this drive is pretty much all new technology compared with those. Only 4 platters (current WD 4TB drives require 5 platters), and it really is nearly silent and vibration free -- much better even than the WD 3TB (5 platter?) drives I have.

Time will tell, but meanwhile I'll just continue to keep full backups.

4TB is still significantly i.e. much more than double the price of 3TB though. Is it really worth it or you need the single drive?

3TB is very much the sweet spot.

Well, that's the thing. Here, a 3TB WD Green drive is currently CAD$130. The 4TB Seagate is CAD$190. The 4TB WD Black is around CAD$300 by comparison. The problem with my MythTV box is that it has only 3 internal drive bays, which are already filled with 3TB drives.

Actually, I've installed the 4TB into that box as a fourth drive, by suspending it over top of the motherboard/RAM area (horizontal case). Some trickery was required.

Edit: I expect prices to remain fairly constant until WD releases their own "Green" (and "Red") 4TB drives this summer. If the Seagate is still behaving itself then, I might buy a few more of them once prices come down more. Note that these drives are equivalent to the WD "Red" series (5900rpm, TLER, etc..).

Cheers

I should have qualified with my location to be clear. Those new Seagates haven't made it to our shores either - not available from my local cheap parts store.

I bought a 3TB WD green for AUD$135 just this week so similar money to you. A 4TB WD black is $350 though and other 4TB drives go up significantly from there.

Edit: Maybe they have but from the online retailers starting from about $220 + $10-20 shipping. I usually buy from my local guy since it's easier and usually cheaper.

Here're the "Shopbot.ca" search results for the new Seagate 4TB, with prices in CAD$ (for me, at least). Some of these places will ship internationally, though I think that's a bad way to purchase a sensitive mechanical device like a multi-TB hard drive.

http://www.shopbot.ca/m/?m=ST4000DM000

Yeah we have shopbot too as well as other similar ones - that's how I found they were avaialble. Just replace .ca with .com.au

Shipping is also usually a deal breaker when you're looking at $/GB.

I'm really looking forward to the WD 4TB drives, indeed as shown on a leaked roadmap meant to be released Q3. On the other hand that same roadmap also mentions a Green 5TB drive to be released in Q4. IF that is true, that might drive the price of the 4TB drives down faster.

Back to this again. Last night, SWMBO & I were watching a BRRip of Fame(1980). Really good film, especially the cafeteria party scene. But playback stuttered annoyingly during that scene, which has a lot of fast movement, camera panning, and high bit-rate audio.

Today I poked at things, and noticed that the file plays more smoothly (though not perfectly) when not passing through mhddfs. I think mythtv doesn't do enough read-ahead, an issue that is compounded by the frontend streaming content via the backend, rather than just reading the file itself.

So I patched the kernel on that box to intercept open() calls to the videos hierarchy on the mhddfs, redirecting access straight to the underlying files when the open() is for an ordinary file read. Doing this similarly reduces the stuttering we saw to almost non-existent levels.

Someday I've gotta figure out where Mythtv itself does the file reads, and insert an fadvise() call there for proper read-ahead, or something.

Cheers

Excluding mhddfs completely since I'm not using it, I see similar results in MythTV in what I assume are high bit rate portions that could easily be resolved with a bit of buffering.

I have all my TV on a NAS connected via HomePlug powerline so it's not the speediest in the world - maybe 2-3MByte/sec average.

The untuned signal at the beginning of HBO shows reliably stutters (probably doesn't help it's right at the start though). Certainly sections where bitrate should go up cause problems.

On a completely different note, do yourself a big favor and pick up this. In my experience, it's perfect for the same use cases where people usually turn to powerline. If you have a cable jack anywhere near both ends of that run, you'll be FAR, FAR better-off with MoCA adapters. The speed will be almost 100x better. I used MoCA adapters throughout my condo (before I moved into a house with ethernet), and I never saw speed issues.

MoCA is amazing...

Well based on the numbers mentioned it would be more like 10x. I get somewhere in the 20-40Mbit/sec range and have seen 50Mbit at some point (I said Mbyte/sec before).

I don't have cable at both ends either so no use to me. I'm considering looking at Wifi N. From the living room I easily get 12-14 MByte/sec from my router on 802.11n 5GHz to my laptop. However I feel the problem is more MythTV's lack of buffering than anything...

Well normally, my MythTV box can play back anything I throw at it, without even a hint of stutter. To get it to that point, I've patched bugs in MythTV, installed an NVIDIA GT240 video card for pure VDPAU playback at the highest quality settings, made the appropriate configuration tweaks to have the HDMI output match the refresh rate of the source material (the video file), etc..

I'm not used to seeing stutter or even the slightest jitter from anything on it. So kinda surprising to get it from a 3GB video file. Definitely a buffering issue, because one can hit the "15sec back" button and have it replay the stuttered scene (from the page cache) without any hint of stutter second time around.

I might poke at it more if I see the problem again with some other file.

Cheers

Only peripherally related to this discussion, but...

My internet comes to me on a 15Mbit/sec cable modem and a WRT54G2 router. My computer and SWMBO's computer are wired directly to the router with Ethernet. My downstairs neighbor (and the one below her) are using the wireless signal from the router. (It's a bit more complex than that: they receive their signal from a second WRT54G that is being used as a repeater from my WRT54G2 because there is so much steel in my house that my signal can't propagate directly to them.)

I have run speed tests and I do receive consistent 14-15 Mbit/sec downloads at my directly-wired computer. Can my downstairs neighbors expect to receive comparable speeds after going through the two wireless routers?

tanstaafl.

What speeds are they actually getting?

Expect is a loaded question, as there are multiple variables involved. The WiFi repeater effectively halves the effective bandwidth available to everything connected through it. Whether that has much impact depends on how much bandwidth is available to begin with, on each hop.

Tivo sell what I think i the same one for a few dollars cheaper. I believe this is their preferred method for streaming to the Mini, that or ethernet, but wireless, even N, is right out..


Depending on how things work out over the next few months, I may be coming to you for MoCA advise.

Probably not. As a rule of thumb, take whatever "speed" a wireless gizmo advertises, and divide it by two to get a real-life baseline for any use that doesn't happen within the same room. In your case, this (26mbits/sec) is still faster than your Cable modem, so no loss here. This gives 15mbits/sec over the first wireless link.

Then divide by perhaps two again, to account for the (half-duplex) relay.

So in her setup, I'd expect to be able to stream at a steady 7-8mbits/sec in real-life. Maybe better, if the sun, moon, and planets are in The Correct Alignment.

Cheers

Ah, my fault, I read MB as Mb in your previous post.


Yup, Tivo relies on MoCA for the Mini (or ethernet) and I believe can also talk between regular Tivo units the same way. It's also the way many (most? all?) cable providers are handling in-house place-shifting of content.

You're also right that it seems Tivo is charging a little less for those things, though I get two-day shipping through Amazon


Happy to give it! It's pretty straightforward, with a couple little potential snags.

N throws more variables into the puzzle then A, B or G did. (Posting for general info)

1. Is it 2.4 or 5GHz? - 5GHz has more channels, thus less overlap and interference. Downside, signal doesn't travel as far.
2. Are "wide" channels in use? 802.11n allows the old sized 20MHz sized channels, and wider 40MHz channels. Potential to double speed.
3. How many radios and antennas? Most equipment has 2, leading to a possible 300Mbit rated link when using wide channels. Some devices may only have one, capping it at 150MBit. Other options are 3, and the spec allows up to 4 (600Mbit max).

When shopping for 802.11n, keep in mind the above info to try and meet whatever speeds are needed. Distance and overhead will of course slow down these speeds in real world situations. The ability to close in on 450MBit has negated the need for Gigabit ethernet to my laptop in many situations. The upcoming 802.11ac standard should remove the wired need completely for my laptop.

Yep aware of all of that. I have a 2x2 connection at the moment on 5GHz. It's only from one floor to another directly on top (albeit through a concrete slab).

However as mentioned, I'm not sure this will actually make much difference due to MythTV's buffering. I've been meaning to run a wired 100Mbit (or maybe even Gbit) just to try it out. If that's no good, WiFi is no chance...

For nearly everything, MythTV here plays perfectly well over GigE. It's just a couple of recent files I've first/ever seen any hint of stutter on.

I had a friend trying to get MythTV to play stuff smoothly from his NAS, over Wifi, then over Powerline networking, and it was a real nightmare. I don't remember what the final solution was there.

Hi everybody,

I have to bring up this thread again because I'm not sure if my thinking is correct:



I also want to use mhddfs to create a storage pool and want to having directly access to the drives on writing (so that I can handle the place where each file is located on the drive I want to be). I don't want to let mhddfs manage the place/drive were my files shall be written, I want to keep this in my hand. But when accessing to the pool for reading, I want do this via mhddfs-mount-point.

I couldn't find an absolute answer although xmodder asked before, so here my questions:

1) Can I have direct access to the drives for writing?
2) Are the files I've written directly to one of the individual drives immediately shown in the mhddfs pool?
3) Or do I have to rebuild the mhddfs pool each time I write data by my own?
4) How can I use aufs and does it make sense to integrate aufs?

Many thanks in advance for any help.

Greets

Yes, no problem at all, no confusion.

Yes, immediately. Mhddfs never caches any metadata. Bad for performance, but good for directly accessing the member drives.

No.

For what you are doing, aufs (aufs2 ?) may be a better choice. It provides the functionality you need: read access to everything under a single mount point, write access to individual members. The reason to perhaps prefer mhddfs over aufs, is if you want the filesystem to automatically figure out where to store stuff. Otherwise, aufs will have higher performance (being an in-kernel filesystem).

Cheers

Perfect, thanks mlord.

That's all I wanted to know, and the best information you gave: I can make it with aufs without mhddsf.

I thought aufs would only create an overlay-filestructure to get a kind of virtual access, but if aufs is able to create a pool with a single-mount-point without any balancing I'm happy for the rest of this week (and above)...