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wallydaw · 13-01-2016, 14:33

I am very much a newbie to the world of Linux, and I would love to know if anyone can enlighten me about network absolute paths.
I have just got a Raspberry Pi and installed Minimserver and Minimstreamer. BBC Radio HLS AAC streams are working fine with the ContentDir in the suggested absolute path, on the micro SD card.
When I try to add another ContentDir pointing to a WD My Cloud NAS where the music library is, I get an error message such as 'Not an absolute path' or 'invalid file name' when I copy the path from the Pi File Explorer to the field or with just about any combination I can think of. The network is a Windows network.
I know that trying to use an NAS as the source of the music files may be a bit shaky, because of the heavy network load that would be involved. For the moment, I'm resorting to a USB hard drive plugged into the Pi as the music library.
Any help or comments such as 'don't go there!!!' would be greatly appreciated!

tboooe · 13-01-2016, 23:26

(13-01-2016 14:33)wallydaw Wrote: I am very much a newbie to the world of Linux, and I would love to know if anyone can enlighten me about network absolute paths.
I have just got a Raspberry Pi and installed Minimserver and Minimstreamer. BBC Radio HLS AAC streams are working fine with the ContentDir in the suggested absolute path, on the micro SD card.
When I try to add another ContentDir pointing to a WD My Cloud NAS where the music library is, I get an error message such as 'Not an absolute path' or 'invalid file name' when I copy the path from the Pi File Explorer to the field or with just about any combination I can think of. The network is a Windows network.
I know that trying to use an NAS as the source of the music files may be a bit shaky, because of the heavy network load that would be involved. For the moment, I'm resorting to a USB hard drive plugged into the Pi as the music library.
Any help or comments such as 'don't go there!!!' would be greatly appreciated!

Can you please let us know exactly what you typed in to the content.dir property for the NAS? When I got the "not valid file name" error it was because my permissions were not set up right for that folder. Check out the log when you enter the path and see what kind of error you get.

wallydaw · 14-01-2016, 18:59

(13-01-2016 23:26)tboooe Wrote:
(13-01-2016 14:33)wallydaw Wrote: I am very much a newbie to the world of Linux, and I would love to know if anyone can enlighten me about network absolute paths.
I have just got a Raspberry Pi and installed Minimserver and Minimstreamer. BBC Radio HLS AAC streams are working fine with the ContentDir in the suggested absolute path, on the micro SD card.
When I try to add another ContentDir pointing to a WD My Cloud NAS where the music library is, I get an error message such as 'Not an absolute path' or 'invalid file name' when I copy the path from the Pi File Explorer to the field or with just about any combination I can think of. The network is a Windows network.
I know that trying to use an NAS as the source of the music files may be a bit shaky, because of the heavy network load that would be involved. For the moment, I'm resorting to a USB hard drive plugged into the Pi as the music library.
Any help or comments such as 'don't go there!!!' would be greatly appreciated!
Can you please let us know exactly what you typed in to the content.dir property for the NAS? When I got the "not valid file name" error it was because my permissions were not set up right for that folder. Check out the log when you enter the path and see what kind of error you get.

I'll try this again tomorrow and check the permissions for the folder on the NAS. Thanks for the hint.

simoncn · (This post was last modified: 14-01-2016 23:13 by simoncn.)

(13-01-2016 14:33)wallydaw Wrote: I know that trying to use an NAS as the source of the music files may be a bit shaky, because of the heavy network load that would be involved. For the moment, I'm resorting to a USB hard drive plugged into the Pi as the music library.
Any help or comments such as 'don't go there!!!' would be greatly appreciated!

You will get much better performance with the library on a USB-attached hard drive than on a NAS accessed via a network share, so I would agree with your suggestion of "don't go there". Confused

Edit: To clarify, "performance" in the above comment is referring to rescannnng performance (see later discussion on this thread).

tboooe · 14-01-2016, 19:26

I will say that yes library scanning from the NAS is slow. However, once scanned I have had no issues with playback on my network and I stream wirelessly. Therefore, I do not think you using a NAS is a "dont go there" issue.

DavidL · 14-01-2016, 22:48

Unusual but I need to disagree with Simon.

While a direct-coupled USB hard disc will give a higher data transfer rate than a network NAS, this is largely irrelevant for streaming music files because the data transfer rates required are relatively low compared with (for example) streaming video. Even if your library consists entirely of 24 bit / 192 kHz uncompressed audio the data transfer rate required will be far less than if you streamed normal HD video. Hence I agree with tboooe.

Perhaps I should add that if your NAS is regularly accessed by several users streaming music and video you may well hit data transfer problems, but this setup is very different from a single-user USB hard disc.

simoncn · 14-01-2016, 23:04

(14-01-2016 22:48)DavidL Wrote: Unusual but I need to disagree with Simon.

While a direct-coupled USB hard disc will give a higher data transfer rate than a network NAS, this is largely irrelevant for streaming music files because the data transfer rates required are relatively low compared with (for example) streaming video. Even if your library consists entirely of 24 bit / 192 kHz uncompressed audio the data transfer rate required will be far less than if you streamed normal HD video. Hence I agree with tboooe.

Perhaps I should add that if your NAS is regularly accessed by several users streaming music and video you may well hit data transfer problems, but this setup is very different from a single-user USB hard disc.

The issue with a network-attached NAS isn't data transfer rate. It's rescanning performance, which could be 5x or 10x worse than a USB-attached drive.

DavidL · 15-01-2016, 10:34

(14-01-2016 23:04)simoncn Wrote: The issue with a network-attached NAS isn't data transfer rate. It's rescanning performance, which could be 5x or 10x worse than a USB-attached drive.

OK Simon, I understand. Why is rescanning so slow on a NAS? The read heads have to do the same work traversing the platters, for a given disc capacity. Is it a result of having RAID on the NAS, or indexing giving a more rapid search on a USB disc? I've setup indexing on my Synology DS412+ but not noticed any reduction in rescanning times.

simoncn · 15-01-2016, 11:00

(15-01-2016 10:34)DavidL Wrote: OK Simon, I understand. Why is rescanning so slow on a NAS? The read heads have to do the same work traversing the platters, for a given disc capacity. Is it a result of having RAID on the NAS, or indexing giving a more rapid search on a USB disc? I've setup indexing on my Synology DS412+ but not noticed any reduction in rescanning times.

Rescanning on a NAS isn't slow if MinimServer is running on the same NAS, so it isn't related to RAID. I think it is probably caused by the way Java's support for scanning a directory tree interacts with the SMB/CIFS protocol for accessing a remote network disk. I have looked at the network messages that are exchanged during scanning but my knowledge of the SMB/CIFS protocol wasn't sufficient for me to identify a specific cause. I don't think there is much I can do about this because MinimServer is limited to using the directory scanning APIs that Java provides.

DavidL · 15-01-2016, 16:26

(15-01-2016 11:00)simoncn Wrote:
(15-01-2016 10:34)DavidL Wrote: OK Simon, I understand. Why is rescanning so slow on a NAS? The read heads have to do the same work traversing the platters, for a given disc capacity. Is it a result of having RAID on the NAS, or indexing giving a more rapid search on a USB disc? I've setup indexing on my Synology DS412+ but not noticed any reduction in rescanning times.

Rescanning on a NAS isn't slow if MinimServer is running on the same NAS, so it isn't related to RAID. I think it is probably caused by the way Java's support for scanning a directory tree interacts with the SMB/CIFS protocol for accessing a remote network disk. I have looked at the network messages that are exchanged during scanning but my knowledge of the SMB/CIFS protocol wasn't sufficient for me to identify a specific cause. I don't think there is much I can do about this because MinimServer is limited to using the directory scanning APIs that Java provides.

Thanks for the detailed response Simon.