HD round robin writes? -MCE

[lameid]

I have a slightly aged PC (DDR2 4GB Duo 3Ghz) that I recently put a four tuner recorder in for Media Center (64 bit Home).

I think I have some read/write slow downs causing performance issues when I am recording multiple shows and attempting to process recordings for commercial skipping all on the same drive. The obvious solution to me is to round robin the drives for recording thereby spreading the drive access efforts around, this of course is not built into MCE. I know DVRMS toolbox could theoretically move some or all the recordings before processing but that is just more drive throughput.

I am also well beyond the volume size my bios supports for RAID...

Any thoughts?

 

[rclarke250]

How many hard drives? what size? what speed? I have 2 ceton quads in an I5-2400, and networking 4 tuners to a core 2 duo 2.8Ghz, with 4 GB of DDR2, and a single 1TB drive, I can record 3 shows, and watch one, or record 4 and watch a recording, and I don't have a slow down on the dual core. Now I used to offload to another PC to remove commercials and such, but now I am just too lazy and don't care, and there is nothing I'm keeping more than a few months. If I want to watch older stuff, that is what Netflix, and Streampix is for. If you are talking the old Pentium D procs. they don't work as well as the core 2's or the I series for mult-threaded applications. How much cache does the cpu have? Mine is a Wolfdale E7400 with 3MB of cache and a FSB of 1066 Mhz. Another thing you could do, is automate batch processing for the middle of the night or day, when you have little to no recordings going on.

 

[lameid]

To restate what I'm asking for...

I have 2 Physical drives that are 2 logical drives. I have a program that writes to one path. I want to round robin the file writes while existing activity is happening on the volume. That said, on to answering questions...

Processor is a DUO not a D... E8400 3.0 Ghz 6MB L2 cache
System has 3 identical HD's (ST31500341AS) 32MB Cache 1.5 TB
Ceton InfiniTv 4 USB

I had intended to RAID 5 the HD's but the Mother board / Bios has some sort of capacity limitation for RAID.
So what I have is 3 Logical drives, 1 associated with each physical drive. 2 drives are configured for playback. I have some old 480i recordings dropped on the one that is not recording to. Perhaps showanalyzer is junk and when I finish the Paypal TOS I can get the contributor version of Comskip. I think the skip files were set to drop or process on C: (boot drive) whereas the recordings were on D:... but I didn't dig too much on my first attempt so far.

I can record 4 shows and watch another. I use Recorded TV HD add-in and like it. I had to roll back to kill an install of DVRMS Toolbox and show analyzer (some patches and Recorded TV HD went too). With DVRMS Toolbox loaded, I was seeing MCE transition poorly in comparison to them not installed, playback was horrible recording shows, buffering issues as well and skipping did not work well as in when I pushed the button sometimes 10-30s later it would skip if at all. Perhaps my install went sideways as even removing registry settings was not working for me to kill DVRMS toolbox. That or the documentation isn't there.

The issue I have in waiting to process content is that I often start watching a show after the first 30 minutes of hour long shows as this is a slow season. I guess I could revisit some of my older content... Several years ago I recorded a Charlie Jade in 480i (it is HD) and only got half way through watching it before shelving my then new/current HTPC because the Analog card did not have drivers that support more than 2GB of ram and I was making less money and the InfiniTV4 was still $400 then... Wish the old card did work as it has an FM tuner and would be handy as would the RCA inputs for Analog conversion... I guess that's why the XP media center system is still around even if it hasn't seen power in years.

Although if I waited to process content, I suppose I could simply manually skip the recordings in the interim. It is a minor inconvenience for me but there is someone in my house that is bothered by the screen flashes of skipping repeatedly and the auto-skip is nice to avoid it.

 

[rclarke250]

I am still confused, On line 2 you say you have 2 Physical HDD's. Then in line 7 you say So what I have is 3 Logical drives I associated with each Physical drive, 2 are set for playback????? How many arrays do you have? how are the arrays configured? Please tell me you didn't set a logical drive to a single physical drive, because that would accomplish absolutely nothing but add overhead to the storage subsystem. I think what you need to invest in is an actual hardware raid card, as this would offload to the card the storage stuff, and leave the cpu for other stuff. As to Duo as the name of the cpu, it is a core 2 duo, the only duo cpu was a mobile proc. hence why I was not understanding as you gave no other specifics as to what the specs for your system were.

 

[lameid]

Line two is in scope to what I want to accomplish... round robin two drives for recording. The hardware list has 3 Physical drives... I meant logical generically... Three drives three primary partitions or whatever they're called these days.

 

[hairlessupportmonkey]

You can create a software raid in windows.

http://www.howtogeek.com/howto/36504/how-to-create-a-software-raid-array-in-windows-7/

ACSS - SME
General Geek

 

[lameid]

Yes software RAID exists... Not sure how that is in any way relevant other than I have confirmed I'm not using it and it could be a problem if I did.

 

[hairlessupportmonkey]

but creating a RAID set is your only real way of achieving this. A hardware RAID card, as stated, will fulfil your request. However in saying that, some drives in RAID 0, 5, 10 will not keep up with fast read and writes, especially large drives and volumes and also the technology used with the drives, such as seek times etc. Its a bit of a black art.

How about a NAS drive on a gigabit network. That will write at around 20MB / sec and read much faster. I use a NAS for storing HD movies and playback is fine.

ACSS - SME
General Geek

 

[rclarke250]

So do I , all of my movies and music is on my NAS, and then I have 2 machines recording TV from 8 tuners that are configured as network tuners, so I burned out 2 cheap gigbit D-Link green switches, now I have 2 8 port Trendnet, and we will see how these fair. Both D-links failed about 16-18 months old. But raid card is the only way I know of to do sequential writing to different drives, because that is what a raid 5 will do. Just lays it down in stripes, and parity bit instead of synchronous files.

 

[lameid]

RAID 5 may write to two drives with every write. The 'target drive' and the parity drive. It has to read from all the other drives (Spanning) to compute the parity data. So writes tend to be a bit intensive. However, Reads are typically exceptionally fast from RAID 5 by comparison. I don't think there is a requirement to round robin the spanned or non parity drive and sctually would be a bad idea for some applications i.e sequential database data. Then again a database is typically one file... worth digging on I suppose but I was hoping for a software minimally invasive solution...

 

[rclarke250]

UUmmm, there is no parity drive in a raid 5, all data striped and parity is distributed. And yes it is a ton of writing....It writes to all the drives for every write function.

RAID

 

[lameid]

I see it was explained over simplified to me... RAID 4 is what I understood as RAID 5... Raid 5 - block striping and distributed parity (blocks spread accross drives as is parity data). Still one drive failure tolerance in an array and still slower writes. If drive throughput is the issue, I don't see RAID helping except mayybe mirroring which potentionally could speed up read throughput by allowing concurrent reads.

With any luck when I get to digging at it, it won't be the drives causing the performance problem or I can figure something else out.

 

[hairlessupportmonkey]

RAID 4 (block-level striping with dedicated parity) is equivalent to RAID 5 except that all parity data are stored on a single drive. In this arrangement files may be distributed among multiple drives. Each drive operates independently, allowing I/O requests to be performed in parallel.

Mirrored sets will not help. they are designed for redunancy and not read write access. you will have just one drive to read write to but with a mirrored drive as a "backup" if the main drive fails.

RAID WILL increase your performance for the task you have at hand.

ACSS - SME
General Geek