dedicated drive for videocapture: raid 0 needed ?

[VJ]

Hello,

It is common knowledge (unless I'm mistaken here...?) to use a dedicated drive for videocapture. My system currently has nothing but SCSI-drives, but acquiring larger drives (for videocapture) is more expensive.

Is a single dedicated IDE or firewire drive (7200 RPM) sufficiciant for DV capture, or is it perhaps better to put 2 drives in (software)RAID 0 ?

Current drive config:
Onboard U320 channel A:
Quantum Atlas 10K (to arrive this week, replaced under warranty)
IBM Ultrastar 36LZX
Seagate Cheetah 10K.6

IDE:
Toshiba SDM-1612 (dvd-rom drive)
Plextor PX 708A (dvd recorder - to arrive this week)


Jörg

[LvR]

Depends on the editing software abilities - if you are looking at working only with a single stream, then no need for Raid.

DV runs at about 3.5M/s so its a doddle for any current drive.

[Dr Mordrid]

Generally *.avi editing (usually MJPeg) doesn't need RAID unless you're capturing/editing uncompressed files (HuffYUV, YUV, YUY2, RGB24 or image sequences).

DV editing rarely needs RAID with the exception being when you use RGB24 or YUV files in the project (20-30 mb/s bitrate can be tough to get on inner tracks of a single drive).

Hardware RT systems rarely need RAID, and in fact a RAID can often choke the PCI bandwidth needed by cards like the RT.X100 or Storm2 to operate smoothly.

Software RT systems to the contrary would need RAID once you get past a few complex layers.

Dr. Mordrid

[VJ]

ok, thanks!
I figured as much, but wanted to make sure. To buy a scsi-drive for only this purpose seemed overkill (and expensive)...

edit: thanks DrMordid (your reply came before mine)

Jörg

[VJ]

Would this be fast enough:

http://www.lacie.com/products/product.htm?id=10081

RPM: 7200
Interface Transfer Rate: FireWire 800: 800 Mbits/s (100MB/s), FireWire 400: 400 Mbits/s (50MB/s), USB 2.0: 480Mbits/s (60MB/s)
Max sustained transfer rate: FireWire 800: up to 55MB/s, USB 2.0: up to 34MB/s*
Average seek time (write): 10 ms
Buffer: 2 MB (400 GB), 8 MB (500 GB)

Connection used will be Firewire 800. I assume 2MB buffer is sufficiant ?

Jörg

[LvR]

Max sustained transfer rate: Fire-Wire 800: up to 55MB/s, USB 2.0: up to 34MB/s*

Given the current state of disk technology, I very much doubt that those figures will be achievable in real-life with video capturing or in fact any other app talking to that disk.

Just about all external units I have seen manage only about 60% of what the average UDMA5 disks can manage..........

I reckon if you see 20MB/s you gonna be lucky.

If you bump into any benches thats worth looking at, please post a link so I can be proven wrong.

Also - it depends on which motherboard you going to be using with this thing - it may end up loading the PCI bus if you are not running one of the latest mobos, with the USB2/1394 hanging off the Southbridge directly.

[VJ]

Originally posted by LvR
Given the current state of disk technology, I very much doubt that those figures will be achievable in real-life with video capturing or in fact any other app talking to that disk.

Yes... but then again: 500 GB probebaly means that it will consist of 2 harddisk in RAID0, right ? (to my knowledge no manufacturer makes a single 500 GB disk)

The max sustained rate is most likely the rate from buffer to interface (not from physical platter to interface), as is mostly the case...

Also - it depends on which motherboard you going to be using with this thing - it may end up loading the PCI bus if you are not running one of the latest mobos, with the USB2/1394 hanging off the Southbridge directly.

Mainboard is this one:

http://www.supermicro.com/PRODUCT/MotherBoards/E7505/X5DA8.htm

Firewire host will be this one (once I acquire it; presumable I'll get a sample board if they are still available):

http://www.indigita.com/products/hostadapters/idt804pci.html

Jörg

[LvR]

Jörg

You are right - the lacie uses 2 disks of 250G in a Raid config - no mention of Raid 0 though - my bet is its gonna be a JBOD setup inside that housing, so you will again be limited to effectively the transfer rate of 1 disk only (minus interface overheads - ie - back to square one). The link you provided has a press review link where the word "tandem" is used - perhaps they meant Striped/Raid0 and I am completely wrong.

Very Nice 1394b card that - but I reckon you will be able to get away with a standard 1394 as well.

Lets see what our expert Dr has to say about it all.

[Eddy]

There is a review of external storage solutions on ThG: http://www.tomshardware.com/storage/20030915/index.html

Eddy.

[VJ]

Originally posted by LvR
Very Nice 1394b card that - but I reckon you will be able to get away with a standard 1394 as well.

Yes, but I hate to have to drop the bus speed, I only have 2 PCI32/33 slots and one PCI-X bus also hosts SCSI, the other one also hosts LAN). This is the only PCI-X card I could find, it is not in production yet, but they are trying to locate an engineering sample for me... I hope they find one...

Lets see what our expert Dr has to say about it all.

Yes...


Jörg

[bubu]

I just read an article (interview with Canopus engineers) about capture storage in a Japanese magazine.

They say, "Raid and scisi cards can hog the bandwidth of PCI, which can deteriorate the capture quality"; thus, they recommend a high density simple IDE(ATA133) HDD for capturing.

With the latest HDDs with 80GB per plateau design, the data transfer rate is clocked at least 40Mps (Maxtor 9 series), which is more than adequate for capturing a darn good quality video.

My humble on-board ATA100 raid chip, which holds two western digital 40G HDD on RAID0, can do max 41Mps (clocked by Matrox's HDD utility software).

Thus, I would say "get a 80G HDD for capturing and hook it to your ATA133 IDE connector" for most bang for buck effect.

[VJ]

Originally posted by bubu
I just read an article (interview with Canopus engineers) about capture storage in a Japanese magazine.

They say, "Raid and scisi cards can hog the bandwidth of PCI, which can deteriorate the capture quality"; thus, they recommend a high density simple IDE(ATA133) HDD for capturing.

Thanks...
But euhm, PCI-bandwidth is not likely to be an issue (SCSI is on PCI-X, firewire will be on PCI-X):

http://www.pcisig.com/specifications/pcix_20#overview

The system has 2 independant PCI-X busses (133 MHz and 100 MHz).

But yes, IDE is still the cheapest option, and has become sufficiant for video...


Jörg

[LvR]

It just WAY nicer and more convenient to be able to run around with an external unit between different machines, and impress the hell out of anybody seeing you with that gorgeous thing.

[bubu]

Originally posted by LvR
It just WAY nicer and more convenient to be able to run around with an external unit between different machines, and impress the hell out of anybody seeing you with that gorgeous thing.

....show off...

[bubu]

VJ,
right, obviously the article was meant for an average user, who doesn't use a high end (or Xenon class) system (PCI-X etc) for their video capturing.