Multiple Tuners With Raid 5

[dynaclip]

I have two 7-8 tuner DVR's that need a level of redundancy and stability on par with a business server, aside from redundant power supplies, server motherboards and so on, I would like to implement a raid 5 array of about 1.5 - 2 tb. My question is - if all 7 tuners are recording at once at low or medium record settings will the bandwidth over tax the raid algorithms? If so is it just a matter of higher processor speeds or should I be looking into a raid 1 setup to handle the high write bandwidth?

Thanks,
Tim


FYI: The current DVRS are 1.8 Core 2, Geforce 7300gt, 2 gig ram, 400 gig sata hd, 4 Hauppauge wintv dual tuner cards. (I will use Hardware Raid when implemented)

[dynaclip]

One more question, to add stability and to reduce heat/power I was thinking about running the os off this 2gb ssd found here http://www.logicsupply.com/products/fdm4000i2g it has a 4,000,000 read write endurance. Has anyone done this? Should i go larger say 4gb? I will potentially be setting up quite a few of these dvrs and need to make the entire process as stable and seamless/embedded as posible.

[tscales]

I have a Raid 5 array and the write speed is just too slow for what you suggest. My approach is to record to a standard SATA drive and then have a script that moves the files onto the raid array after all recordings are complete.

The SSD is overkill and outrageously expensive. It would be tough to get XP to fit in 2GB or even 4GB.

[rugby]

I have a 4-drive RAID 5 array on a 3ware SATA RAID card and can record 3 OTA HD tuners to it simultaneously without issue. I'm not sure how 7-8 tuners would work with it but I can sustain 90MBps write speed so it should be fine. The key is to get a good RAID card, not onboard RAID.

[Joey Z]

I am using 8 tuners right now on a RAID-0 setup with no problems. The drive is on a auto backup every night to a separate RAID-1 drive for redundancy.

[Rich A]

If all your capture tuners are analog and have hardware based mpeg-2 encoding, then there would be somewhat less required for I/O throughput to the hard drive system. The top DVD quality mpeg-2 is generally under 9 mbs. And because they are hardware based, there is very little CPU impact.

Almost all of the digital tuners however do not even do any trans coding, but rather just dump the mpeg transport stream directly to the hard disk. The highest throughput you will find there is typically OTA digital stations. In that case you can have up to 20 mbps for a 1080 digital OTA transmission.

Cable and satellite in some cases (because of limited bandwidth) can be as little as half the through put needed as an OTA station. I personally have run a 4 drive raid 0 array in the past dedicated solely for recording. I found it overkill and have since reduced it to a 2 drive array. And I can watch a recorded 1080 HD digital while recording three digital and two analog at the same time. Most this is made possible by the faster latest generation of SATA HDDs.

[tscales]

That's impressive write speed. Mine are in an external eSata enclosure, which could be part of the problem. Works flawlessly for my purposes, with a 3TB array, so I'm happy.

[dynaclip]

Thanks for all the input, I like the idea of keeping the 400 gig with os and using a script to transfer to a raid array each night. Ultimately we are looking into the enterprise solution but $10,000+ is a little steep right now, does any one know how the hard drives are setup in those machines?

[Greg Caulder]

Originally Posted by dynaclip

Thanks for all the input, I like the idea of keeping the 400 gig with os and using a script to transfer to a raid array each night. Ultimately we are looking into the enterprise solution but $10,000+ is a little steep right now, does any one know how the hard drives are setup in those machines?

Right now my setup consists of 3 500GB HDD's in a RAID 5 array. My write speed is in the range of 45megabytes-55megabytes a second. I have 6 tuners, one of them is HD. Ive never had any problems with it.

[GeorgeH]

dynaclip ---

"setting up quite a few of these dvrs and need to make ..."

Not to offend those who make suitability claims but ...

BeyondTV is not suitable for the level of quality you are seeking.

I and several people I work with spent 2-3 months and many dollars documenting defects in BeyondTV. For many of the defects the solution is more speed, more memory, more disk space. But other defects are not fixable.

For 7 tuners and the quality you want requires about $10K of hardware if it is PC/BeyondTV based. There are more cost effective solutions.

[rugby]

Originally Posted by GeorgeH

For 7 tuners and the quality you want requires about $10K of hardware if it is PC/BeyondTV based. There are more cost effective solutions.

$10K?!?!?! No way.

[dynaclip]

So far our two 7 tuner DVR's (under $1k a piece) have worked great with beyond tv, we have been using them for about 3 months with fine results, all we are looking for right now is the storage space (in the future the search-ability of the enterprise system is just what we are looking for) and reliability that is why I am looking into the raid configurations. Also does anyone know of a good file transfer script? Or could you send me in the right direction on writing one my self. Thanks

[queonda]

You can use the showsqueeze to just copy to another location.

[Jakesty]

You can use one of Microsofts free programs SYNC TOY or possibly Active Sync for your file replication. Sync Toy supposedly does compression before sending the data then decompresses it, reducing the amount of data having to be moved.
You could also use XCOPY and Move, just doesn't do compression
Both programs can be launched as a post process.

Also, don't forget, if you have that many HD or SD shows being recorded, you could just record to a couple of RAID 0 arrays and then do the move later. Some shows could be recorded on different paths/drives which will reduce your throughput per drive array.

[ZetaVu]

Originally Posted by GeorgeH

dynaclip ---

"setting up quite a few of these dvrs and need to make ..."

Not to offend those who make suitability claims but ...

BeyondTV is not suitable for the level of quality you are seeking.

I and several people I work with spent 2-3 months and many dollars documenting defects in BeyondTV. For many of the defects the solution is more speed, more memory, more disk space. But other defects are not fixable.

For 7 tuners and the quality you want requires about $10K of hardware if it is PC/BeyondTV based. There are more cost effective solutions.

The one major defect George has that connot be solved with any amount of money, that is the user himself.

I thought you had left for good Georgie? What brings you back, no one else will play with you?