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tonysss13
20-12-10, 16:09
Hi
I have a TS-859 pro with 5x 2tb drives in a RAID 5 configoration
I use it for streaming lossless blu ray & dvd iso's around the house to various netgear NTV550 streamers.

all are wired and all switches are 1Gb (although the streamers have 100mb nic's)

currently I can stream two BD iso's at once without any problem but a third one causes stutter tue to bandwidth. is there anyway I can improve this or does it sound about the limit for the server?? I am not using port trunking at present would this help and if so can anybody recomend a compatible switch?

the network test on the NTV550 shows a constant 85 to m95mbps from the NAS

thanks

tony

Malignant
20-12-10, 16:45
Reading this i don't think the problem lies with your network.

I think streaming 3 different high bitrate movies just puts to much strain on the HDD's itself.

The network can get Gbit without any problem, but if you want the HDD's to read 3 different sources at the same time you'll run into the limitations of a physical HDD.

Just take a look at this screenie which comes from a HDD roundup.
It shows the maximum read rate's for different HDD's.
http://www.sharkyextreme.com/img/2008/04/samsung_1tb/hdspeed_read.jpg

The avarage HDD can read just over 90mbps. So 2 40mbit blurays works fine, but add a third and your past the limitations of the hdd itself.

The only workaround is using SSD's in your NAS :)

Micker
20-12-10, 17:06
The above hard drive chart shows MB( megabytes) which is about 8x mb(megabits). Blu ray is about 50mb/s, the fastest drive can do about 800 mb/s.

rudku
20-12-10, 18:07
Tip for switch, which supports Port Trunking:
NETGEAR PROSAFE 8-PORT GIGABIT SMART SWITCH GS108T-200
http://netgear.com/business/products/switches/smart-switches/GS108T-200.aspx

My experience with Port Trunking (IEEE 802.3ad) was described here:
http://www.mpcclub.com/forum/showpost.php?p=195410&postcount=177

... but you can get small improvement ...
... my charts in post above support Malignant words, that limit is not a network, but bandwidth of HDDs ...
... and in RAID5 configuration are read speads lower then at single disc configuration ...

Another note about streaming BDs via QNAP NAS:
- I can stream trouble-free BD rips from external HDDs conected to QNAP NAS via eSATA or USB dock
- maybe tip for solution how easy expand NAS, which is closely full
http://www.akasa.com.tw/update.php?tpl=product/product.detail.tpl&no=181&type=Enclosures&type_sub=3.5%20Enclosure&model=AK-IC008

Malignant
21-12-10, 08:45
The above hard drive chart shows MB( megabytes) which is about 8x mb(megabits). Blu ray is about 50mb/s, the fastest drive can do about 800 mb/s.

Completely true.

But you have to account for the fact that it's a physical disc system.

The headers need to navigate to the correct section of the HDD platter where the data is stored. And if you are streaming 3 different sources at the same time the head needs to be in 3 spots at the same time.

This is just not possible physically.
Some of this will be caught by the buffers in the HDD where the information will be "stored" before being streamed to the MP, but the stutter is mostly just buffer underruns.

I can't fill the buffer of the HDD's as quick as it's being depleted.

tonysss13
21-12-10, 11:32
thanks everybody for your posts.

forgive my lack of knowledge but I am using 5x2TB drives in the raid set up. wouldn't this mean that there's a good chance of the three different files being accessed are on different drives so using more than one header to access the files?

would a workaround be to have say 3 raid arrays say one of 2x2tb and two of 3x2tb and hope that the files the kids are watching are on different arrays.

obviously DVD rips are not a problem, but as blu ray becomes more popular I'm worried that the times that 3 are being accessed at once will become more common

twol
02-02-11, 17:54
thanks everybody for your posts.

forgive my lack of knowledge but I am using 5x2TB drives in the raid set up. wouldn't this mean that there's a good chance of the three different files being accessed are on different drives so using more than one header to access the files?



You are using Raid 5, so parity and data are striped ACROSS all drives, so you are LIKELY to get conflicts between all the files that you are trying to read concurrently.