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Problems accurately copying iTunes library


sfdoddsy
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Hi. First post but have lurked and been inspired.

 

One of the inspirations has been to finally try and setup a proper server and backup system. I have 120G or so of music which is stored on my PC laptop. It's a mix of ripped and downloaded, in ALAC, AAC and MPEG. I'm kind of anal about labelling so everything is tagged and sorted. When I replace things in my library I delete from the Music folder.

 

However, as mentioned I've decided to get more serious. I have a spare Mac Mini which I now use as the server, with an external drive holding the files. This is connected to a LaCie Network Space NAS drive for backup, and I'll probably back that up with another drive.

 

However, I'm having annoying issues with what should be the simplest part. When I copied my music from the laptop to the external drive, I had a folder of exactly the same size. However, when I setup the new library on the Mini, it was slightly different in the number of files and size, and I had a few File not founds. I went through and fixed that so it matched the original library and backed it up to the NAS.

 

For some reason the library on the NAS when shared to iTunes on my original PC is 4Gb and 150 or so songs larger. Being anal I went back and did it all again, this time copying directly to the NAS and the Mini, but once again the various libraries do not match although the Music folders they point to are identical.

 

Is there any way to have iTunes properly recognize everything? And any idea how I can get a LaCie library of 125G via sharing when the only folder of music on the NAS is 120G? Or should I just accept slight discrepancies?

 

BTW, if anyone has a LaCie Network Space and also has ALAC files, I've found that transferring via the network makes LaCie degrade them to AAC, whereas a direct connection does not.

 

Anyway, sorry about the long post but any help would be appreciated.

 

Oops, one last thing. Is the Mini always so slow? If I am copying anything over the network it basically becomes useless for any other task. And it can't stream from the server without nasty dropouts. It's an older Intel 1.6 with G wireless, but still. I've streamed an Airport Express and ATV with no such issues.

 

The router is a Netgear 3700

 

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Just a couple of thoughts -

I originally hosted our iTunes library on a Mac Mini - a 2005 Mac mini that is. Only has 512megs of RAM and an 80gb drive in it, and so it has always had a couple firewire connected drives to store the music on.

 

Using the server with a wireless connection turned out to be a bad idea. Dropouts, failures, sometimes pauses in the music. All kinds of odd behavior.

 

Hardwiring the machine to the router eliminated all those issues. My advice for the dropouts is just to located the server, headless if need be, close enough to your router to run an ethernet cable, and turn off the wireless.

 

In the process of figuring that all out however, I initially thought that it was just processor issues. So...

 

I moved the entire iTunes library, which over time has grown to about 600gigabytes, over to a honking big quad core PC. Initially it ran under Vista, but I moved it to Windows 7 the middle of last year. Boy did I run into some odd troubles.

 

I purchased two gigabyte external drives that run on USB, Firewire, or ESATA. I hooked em up as eSATA and they were dynamite fast. But... one or another of the drives would fail every week or two. Just freeze up. So I hooked em up with Firewire.

 

THAT WAS A HUGE MISTAKE. Files would be corrupted as they were copied over from our Macbooks. I could not tell they were corrupted until I tried to play them either. Connecting the drives via USB seemed to fix the problem, but by that time, I was not ready to trust PC anything any longer.

 

So I slapped the two gigabyte drives back on the 2005 model Mac Mini with Firewire, formatted them, and restored the itunes libraries from the Mac backups.

 

The little way underpowered Mac Mini, connected to a gigabit port on our Airport Extreme Base Station, just works. It will stream to three Airport Express locations and drive audio directly from the Mac, all at the same time. No dropouts. And it will copy up new files from out MacBooks while it is doing it. Still no dropouts.

 

And no corrupted files.

 

I am thinking about trying the PC again, but hey- what I should do is just sell the dratted PC and buy a modern Mac Mini. A Quad Core, 2.5ghz, 8gigabyte PC running Windows 7 professional easily shown up by a 5 year old Mac Mini with a 1.4ghz PPC processor. (*sigh*)

 

-Paul

 

 

Anyone who considers protocol unimportant has never dealt with a cat DAC.

Robert A. Heinlein

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Recently I needed to re-install itunes and also found where the regular transfer methods worked in the past, seems with version 8/9 library lists and actuality dont match, if there were say five albums from the one artist, itunes would only index two of them and forget the rest. I tricked itunes into using the old identity of the original install, so at least the iphone would work ok and i didn't need to erase data routine. However the library was a mystery as to why it behaved the way it did.

itunes doesn't like to have a libary in a root of a drive, it needs a folder, eg M:Music. I told itunes that the songs were in m: drive and it put the songs (about 60% of them) into the m:music folder by itself. In the end I deleted the whole library and went to Foobar instead.

 

Network copying is slow, due to the hard disk at the other end. Although you can have fibre cable for networking, the weakest link, the spinning HDD is always slow, windows or OSX. But to drop out over wireless for audio is a problem with interference/DNS issue among quite a few others. I'd check the mini forums at Apple for a start to cure the slowness..

 

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I am not sure how DNS would radically affect transfers over a home network, but I suppose it is possible. The interference is, in my experience, less interference and more contention than anything else, at least as pertains to wireless communications. There is a difference.

 

Only a limited number of wireless units may be transmitting at any one instant, so connecting a server to the network primarily via wireless is not a great idea. Connecting the server physically to a port on a switch means the server never has any contention for the network. Thus, the server can stream to one or more wireless devices with much greater bandwidth and virtually no queing delays.

 

The result is the elimination of, or almost complete elimination of, the dropouts and other streaming problems. Without going through all the math, a simple 100mbs connection on a network switch means the computer can, without contention, receive and transmit about 20 million bytes of information per second- 10 million in and 10 million out. It is a fairly linear scale, so a 1000mbs connection will handle around a constant 20 million bytes per second.

 

On a wireless connection, the same machine may be able to stream about 5 million bytes per second, but, only in half duplex mode. That of course means, it can not receive and transmit at the same time. And worse, it is subject to contention for access to receive or transmit on the wirless network. It is essentially competing with all the other devices on the wireless network for a slot to receive or transmit in.

 

Wireless networks work great for the receiving side though. Devices like an Airport Express can handle streaming audio over wireless networks with near perfection. It is just a matter of quantity. A typical track on a CD represents say, 60 megabytes of data. That data is streamed over say, 3 minutes. That means the server has to provide, over the wireless network, only 335 kilobytes of information per second to the wireless reception point. (60 megabytes / 180 seconds.) Even with fairly congested wireless networks, that isn't usually a problem in terms of reception. Not if the server is directly connected to a switch.

 

The server transmits the data in a timely manner, and any decent switch will bridge or route that much data out on the wireless network without any significant delay. But this is true because the server did NOT have to wait for access to the network. That's kind of inherent in the way access is managed to the type of networks we are talking about.

 

Sorry about the long essay, it is just this is stuff I do know about, and it is nice to be able to share with you guys. Most of you know much more about audio that I will ever know, no matter how hard or long I study. :)

 

-Paul

 

 

 

Anyone who considers protocol unimportant has never dealt with a cat DAC.

Robert A. Heinlein

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Thanks for the replies.

 

I've now tried it by using Genie to back up the music to my NAS drive from my PC, and then copying my PC iTunes library file to the Mac and pointing it to the NAS. This has worked.

 

As for the dropouts, the Mini appears to be fine when no other processes are running. For some reaon it is even better when using Family Sahring from the PC library.

 

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Well, in the case of a client device, it should not have any effect on the sound just because it is cabled - not like the difference between 24g and 6g speaker wire has. I mean it will not intrinsicly make the sound warmer or more distinct, given everything else is equal.

 

It will certainly make a difference if you are in a marginal network environment, though that difference will manifest itself as a lack of dropouts and so forth. The lack of millisecond dropouts is usually audible. It would be interesting to hear if you have tracked the problem down to an interface - which device actually makes the difference?

 

I connect our downstairs blue ray player to the network via a cable because the wireless interface that came with the beastie is of very poor quality. On the other hand, that ethernet cable is plugged into an Airport Express that is simply extending our wireless network and feeding a DAC. The very poor quality wireless interface for the blue ray player is the problem in this case. Still uses the wireless network, it just does not know it. :)

 

Of course, our house is better connected than most office environments...

 

 

 

 

 

 

Anyone who considers protocol unimportant has never dealt with a cat DAC.

Robert A. Heinlein

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