October 19, 200619 yr Well after a month or two of testing, and overwhelming my PCI bus with 3 controllers (10 SATA ports), I'm interested in support for PCI-e (or at least more bandwidth via PCI-X) for better bandwidth management, e.g., the Promise Technology SuperTrak EX8350 8-Port SATA PCI-E. I know it's a sw "Raid" board, but we just need ports and decent performance. A number of 8+ on board SATA ports Motherboard support would be nice as well.
November 6, 200619 yr Author Tom, Any news on supporting high(er) performance PCI-e and higher port density? Obviously, not everyone here has built a 12 drive SATA chassis like I did, or are planing to. Nonetheless- the top function for many Unraids out there is video storage, and as such it would be great to have the ability to build and own a relatively higher performance 12 drive+ chassis to maximize the investment in (parity) drives and other parts. When I say relative performance I would compare it to something like the infrant Xraid class products- one of the things I dislike about infrants kit is that they limit me to 4 drives, and this is the primary reason I went Unraid. Having said all that, I just filled one chassis with DVDs and am looking forward to building another Unraid. If there is a possibility to make another tier of software to support PCI-e/ large array implementations, I for one will be very willing to contribute to the project as I'm sure others using and lurking will as well. No feature(s) is as important to me as: 1. Performance and 2. Data security. -Alex
November 8, 200619 yr I'm sure others using and lurking will as well. yep, you caught me lurking and I'm getting ready to try my hand at a 12 drive SATA system. I second the motion. Too bad promise doesn't offer this without the raid to lower the cost but hopefully they may soon; it seems they are discontinuing all of the (non-raid) sata150 controllers except the 8 port, which does support PCI-X. Odd that it's only PCI-X (non-raid) controller only supports sata150 vice 300. Most of their cards do state some sort of linux kernal support including the one melechmet mentioned.
January 22, 200719 yr Bump... Now I would really like to see this supported. I have a motherboard which the SATA ports are not supported and have 8 drives on the PCI bus. I have 3 PCI-E ports that are unused.
January 23, 200719 yr If I can find and compile the linux drivers for that, I'll put it into my unraid-dev release. May still be a few weeks, but I'll put that into my list.
January 23, 200719 yr If I can find and compile the linux drivers for that, I'll put it into my unraid-dev release. May still be a few weeks, but I'll put that into my list. That would be extraordinarily kind of you. which means I could go up to 12 drives now waaaaahooo. Thanks
January 24, 200719 yr In unRAID storage organization, bear in mind it's unusual to have more than a couple drives active at a time. If you are reading a single file then only 1 drive is active, if writing then only 2 are active (data disk + parity disk). A high speed controller would be useful to decrease the parity-check/sync time, or increase throughput in the case where access is being made to a disabled disk. Hence under normal use, the cost of a high speed controller doesn't make sense for an unRAID server.
February 23, 200719 yr Author In unRAID storage organization, bear in mind it's unusual to have more than a couple drives active at a time. If you are reading a single file then only 1 drive is active, if writing then only 2 are active (data disk + parity disk). A high speed controller would be useful to decrease the parity-check/sync time, or increase throughput in the case where access is being made to a disabled disk. Hence under normal use, the cost of a high speed controller doesn't make sense for an unRAID server. Tom, While my Unraid is not used as a transaction database w/ all disks accessed, multiple drives are still often accessed (more than just 2). An example is 4 rooms with 4 independent media players accessing 4 or more drives, music & video; some writes, most reads. One reason a RAID (whether Unraid or otherwise) is attractive to the home theater person is that you can have multiple streams work as opposed to just one. Vs. something like a SDI modded mega changer which allows you access to one video/audio stream at a time. This is a huge (negative) issue in environments where many people want to watch or listen to different things at the same time under the same roof. In addition to that factor, initial sync and re-sync times are really annoying, 8 to 12 hours re-sync is just crawling. This is going to get worse with more and larger drives.... PCI-e can help all of this to some degree. I think we can at least agree that the PCI bus is inappropriate to host 10+ drives, no?
April 5, 200719 yr PCI-e can help all of this to some degree. I think we can at least agree that the PCI bus is inappropriate to host 10+ drives' date=' no?[/quote'] Ok, to max out the PCI bus you need to have a throughout sustained of > 1 Gbit/second or >125 MB/second you won't run out of bandwidth on "ye good olde PCI" bus. So we have to have 11 drives each sustaining > 11 MB / second. Unless you're talking about sequential I/O and files that are completely contiguous it is unlikely you'll max out the PCI bus. I'm not saying it isn't going to happen, but it's actually a bit more difficult than you might think.
April 5, 200719 yr Author I'm not saying it isn't going to happen, but it's actually a bit more difficult than you might think. Tom was the one that infromed me the PCI bus was saturated when I was complaining about the long wait on parity sync of my 12 drives.
April 16, 200719 yr ... Ok, to max out the PCI bus you need to have a throughout sustained of > 1 Gbit/second or >125 MB/second you won't run out of bandwidth on "ye good olde PCI" bus. So we have to have 11 drives each sustaining > 11 MB / second. Unless you're talking about sequential I/O and files that are completely contiguous it is unlikely you'll max out the PCI bus. I'm not saying it isn't going to happen, but it's actually a bit more difficult than you might think. If this is true, then what is the bottleneck? It isn't CPU, it isn't memory, it isn't the LAN, it isn't the mobo, it isn't the drives, it isn't the SATA interface, and it isn't the PCI bus, so ....? I am in the midst of planning for my Unraid box and I want to focus my $$ on the bottleneck, but can't seem to figure out where it is! Bill
April 16, 200719 yr I assume this takes som real digging to convert theoretical signalling to moviethroughput. IE Your Gigabit LAN will never provide a gigabit/second of movietransfer, and I assume the same goes for the PCI bus, that eventhough it is a 133/66mhz, 64/32bit it still may share that among a few cards, i/o commands, errorcorrection, interference and maybe an card that lowers the speed to 33 mhz for compliance and what have you. /Rene True. I am certainly not looking for 90% of theoretical, I just want to know what is the realistic ceiling for performance and what are the obstacles I need to break down to get there. Bill
April 23, 200719 yr Author There are actually two questions muddled up here. The one I'm concerned with (and this thread started for) is the attempt to mitigate the Internal throughput of a system, not it's maximum external throughput. I know that the PCI bus seriously impedes system performance in my config. If one does the numbers the standard 32 bit [shared] PCI bus is the bottleneck. When I have 12 SATA doing a parity sync it bring my system to it's knees, there is no ifs and or buts about it.. it's a fact. Same configuration with only 3 drives runs way 3x-4x faster.
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