Need help with raid at DVinfo.net

James Brill · January 5th, 2008, 09:59 PM

I currently have the sans digital MS2UT and a mac pro. I realize that I have to buy an external esata card and a rs232 card. For the sata card I was wondering if since I have a free hard drive slot in my mac that I could just get one of those sata connectors that connects to one of the motherboard's and than has an external connector.http://store.sansdigital-shop.com/insatoespcib.html Then with a rs232 card so I can have serial control over things like this drive and maybe a deck in the future, which one is a good one and what company is compatible with the mac pro? Also I have seen usb to rs232 would that work?

Also I have read that with raid 0 and the esata connection my external enclosure will be as fast as if i had just plugged one of the hard drives into the internal bay. Is this true? If so I will scrap this whole plan and just save up for fiber optic one day.

Robert Lane · January 6th, 2008, 09:45 AM

James,

The eSATA 2-bay unit you have is one of the nicer ones on the market; it's great for creating external hot-swap capabilities but, since it's only a 2-drive unit it's maximum throughput is fairly limited and, unlike SCSI or Fiber arrays it can't hold a constant bitrate while it's being used because eSATA has no controller cache to offload drive cache as it builds up. I posted a lengthy article about this eSATA characteristic many months ago here on this forum.

With regard to drive speed comparisons; a 2-drive eSATA array in RAID-0 will initially be faster than a single internal drive however, over time (during heavy editing) the array speed will slow down to no better than a single internal drive, because of the lack of external drive cache, mentioned above. However, there are several other eSATA arrays that would be able to hold higher speeds, and some made by the same manufacturer that you have now, that have 5 or more drives in them. They too still have the same no-external-drive-cache characteristic but because they have more drives available the slowdown isn't as severe. Currently the best eSATA connector type is the Infiniband or Multilane - not to be confused with Port Multiplier, which although seems identical in purpose is not. The direct-connect type, where each drive gets it's own physical connector is the most cumbersome and least efficient to manage.

I would not however suggest you direct-plug any eSATA cables directly to one of the drive slots on the MacPro; you lose both an internal drive slot and and PCI slot at the same time which will seriously limit your future capabilities.

If you need deck control there are a host of options available but have nothing to do with which array type you use.

If you want something future-proof and fast with respect to an external array, wait until Monday, I may have a cost effective Fiber option for you. I'll send you a PM on Monday.

James Brill · January 6th, 2008, 02:33 PM

So I should try and plug the ms2ut into a drive slot itself and forget getting a card for it?

My spending limit is around 800, I capture in hdv but am trying to figure out what to re compress it into, thinking about uncompressed SD, and I have a mac pro but I came from PC's so I am having trouble figuring out raid after barely understanding it for a PC.

Robert Lane · January 6th, 2008, 03:55 PM

Before you start installing anything or purchasing more equipment I'd first suggest you do a lot more research about how RAID configurations work and the options for eSATA connectivity as it relates to your specific hardware setup.

Try talking with Allan @ Omega Broadcast (forum sponsor) or, while not a forum sponsor I'd also suggest contacting OWC (www.macsales.com) and let their sales specialists walk you through the best options for your intended use and your budget.

Also, read up on the implications of any DV codec and workflow; goto www.adamwilt.com and get some technical background in the various codecs before you decide on a workflow. Just so you know, with an $800 budget you'll not come anywhere close to the hardware requirements for working in an uncompressed format, so take that off the options list. If you're working with HDV then the AIC codec would be your best bet.

The option I might have offered is far beyond your budget limits.

James Brill · January 6th, 2008, 05:48 PM

I realize that fibre is expensive and thanks for your time. Also thank you for the links.

January 5th, 2008, 09:59 PM	#1
James Brill Major Player Join Date: Aug 2007 Location: Goleta, CA Posts: 299	Need help with raid I currently have the sans digital MS2UT and a mac pro. I realize that I have to buy an external esata card and a rs232 card. For the sata card I was wondering if since I have a free hard drive slot in my mac that I could just get one of those sata connectors that connects to one of the motherboard's and than has an external connector.http://store.sansdigital-shop.com/insatoespcib.html Then with a rs232 card so I can have serial control over things like this drive and maybe a deck in the future, which one is a good one and what company is compatible with the mac pro? Also I have seen usb to rs232 would that work? Also I have read that with raid 0 and the esata connection my external enclosure will be as fast as if i had just plugged one of the hard drives into the internal bay. Is this true? If so I will scrap this whole plan and just save up for fiber optic one day. Last edited by James Brill; January 6th, 2008 at 12:04 AM.

January 6th, 2008, 02:33 PM	#3
James Brill Major Player Join Date: Aug 2007 Location: Goleta, CA Posts: 299	So I should try and plug the ms2ut into a drive slot itself and forget getting a card for it? My spending limit is around 800, I capture in hdv but am trying to figure out what to re compress it into, thinking about uncompressed SD, and I have a mac pro but I came from PC's so I am having trouble figuring out raid after barely understanding it for a PC. Last edited by James Brill; January 6th, 2008 at 03:50 PM.

January 6th, 2008, 09:45 AM	#2
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,823 Images: 15	James, The eSATA 2-bay unit you have is one of the nicer ones on the market; it's great for creating external hot-swap capabilities but, since it's only a 2-drive unit it's maximum throughput is fairly limited and, unlike SCSI or Fiber arrays it can't hold a constant bitrate while it's being used because eSATA has no controller cache to offload drive cache as it builds up. I posted a lengthy article about this eSATA characteristic many months ago here on this forum. With regard to drive speed comparisons; a 2-drive eSATA array in RAID-0 will initially be faster than a single internal drive however, over time (during heavy editing) the array speed will slow down to no better than a single internal drive, because of the lack of external drive cache, mentioned above. However, there are several other eSATA arrays that would be able to hold higher speeds, and some made by the same manufacturer that you have now, that have 5 or more drives in them. They too still have the same no-external-drive-cache characteristic but because they have more drives available the slowdown isn't as severe. Currently the best eSATA connector type is the Infiniband or Multilane - not to be confused with Port Multiplier, which although seems identical in purpose is not. The direct-connect type, where each drive gets it's own physical connector is the most cumbersome and least efficient to manage. I would not however suggest you direct-plug any eSATA cables directly to one of the drive slots on the MacPro; you lose both an internal drive slot and and PCI slot at the same time which will seriously limit your future capabilities. If you need deck control there are a host of options available but have nothing to do with which array type you use. If you want something future-proof and fast with respect to an external array, wait until Monday, I may have a cost effective Fiber option for you. I'll send you a PM on Monday.

January 6th, 2008, 03:55 PM	#4
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,823 Images: 15	Before you start installing anything or purchasing more equipment I'd first suggest you do a lot more research about how RAID configurations work and the options for eSATA connectivity as it relates to your specific hardware setup. Try talking with Allan @ Omega Broadcast (forum sponsor) or, while not a forum sponsor I'd also suggest contacting OWC (www.macsales.com) and let their sales specialists walk you through the best options for your intended use and your budget. Also, read up on the implications of any DV codec and workflow; goto www.adamwilt.com and get some technical background in the various codecs before you decide on a workflow. Just so you know, with an $800 budget you'll not come anywhere close to the hardware requirements for working in an uncompressed format, so take that off the options list. If you're working with HDV then the AIC codec would be your best bet. The option I might have offered is far beyond your budget limits.

January 6th, 2008, 05:48 PM	#5
James Brill Major Player Join Date: Aug 2007 Location: Goleta, CA Posts: 299	I realize that fibre is expensive and thanks for your time. Also thank you for the links.