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Warner (Mar 11 2009)
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1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
How about an IEEE 1394 raid cluster with it's own ps+case? Then can ship whole enclosure an no need for hot swapping. Something like this would likely work because the drive connectors aren't being cycled. |
Zydor Send message Joined: 4 Oct 03 Posts: 172 Credit: 491,111 RAC: 0 |
Already said by many - worth repeating nonetheless. Thank You Matt for taking the time and trouble to Post these Notes. It helps enormously to understand what you guys are doing for all of us, the hassles you go through, and the times when you need the space to do it without excess Posted questions. During the tough times, keep smiling, there are a huge number of people that you help by what you do. All of you over in the emporium make our lives easier, the silent majority are willing you on, posts or no posts. There are few things that can be as rewarding in what you all do, nor appreciated so much by so many. Regards Zy |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 31014 Credit: 53,134,872 RAC: 32 |
Thanks for the update. Wish I had a solution, but with the strong possibility of Arecibo going dark I know spending money isn't in the cards. |
Borgholio Send message Joined: 2 Aug 99 Posts: 654 Credit: 18,623,738 RAC: 45 |
Thanks for the update. Wish I had a solution, but with the strong possibility of Arecibo going dark I know spending money isn't in the cards. Well if Arecibo does go dark, what would Seti@home likely do? I asked that question in the Seti@home Science forum but never got an answer. :-( http://setiathome.berkeley.edu/forum_thread.php?id=52239 You will be assimilated...bunghole! |
Westsail and *Pyxey* Send message Joined: 26 Jul 99 Posts: 338 Credit: 20,544,999 RAC: 0 |
*chuckle* "The most exciting phrase to hear in science, the one that heralds new discoveries, is not Eureka! (I found it!) but rather, 'hmm... that's funny...'" -- Isaac Asimov |
Virtual Boss* Send message Joined: 4 May 08 Posts: 417 Credit: 6,440,287 RAC: 0 |
Well if Arecibo does go dark, what would Seti@home likely do? I asked that question in the Seti@home Science forum but never got an answer. :-( Here's a crazy idea? Maybe the crunchers on each continent could put dishes on their roofs,point them all at the samesame part of the sky, sync them with GPS timing and we could start another boinc project to combine all the outputs into one data stream for Seti. The effective dish size would be orders of magnitude larger than Aricebo, there would be more than one part of the sky being scanned simultaneously, and localised interference would get swamped by the overall signal combining. High speed internet connection would be needed though. Apologies to dial-up users. |
Jesse Viviano Send message Joined: 27 Feb 00 Posts: 100 Credit: 3,949,583 RAC: 0 |
I noticed that the maximum data file size on the server is 50.20GB. If you could tell them to record slightly shorter file sizes, could you instead go to double-layered BD-R (Blu-Ray Recordable), which max out at 50GB? BD-RE (Blu-ray Rewritable) might or might not be practical because nobody has produced a double-layer version, so they currently max out at 25GB. |
ML1 Send message Joined: 25 Nov 01 Posts: 21241 Credit: 7,508,002 RAC: 20 |
I noticed that the maximum data file size on the server is 50.20GB. If you could tell them to record slightly shorter file sizes, could you instead go to double-layered BD-R (Blu-Ray Recordable), which max out at 50GB?... How durable are they and what cost for the drives and media? And will they survive 24/7 operation? The drives will also need to automount the media or you'll need lots of drives! (There's no students to spare to keep feeding disks!) Otherwise, how does 2-bay or 4-bay NAS enclosures with Gbit ethernet compare? Keep searchin', Martin See new freedom: Mageia Linux Take a look for yourself: Linux Format The Future is what We all make IT (GPLv3) |
KWSN THE Holy Hand Grenade! Send message Joined: 20 Dec 05 Posts: 3187 Credit: 57,163,290 RAC: 0 |
I noticed that the maximum data file size on the server is 50.20GB. If you could tell them to record slightly shorter file sizes, could you instead go to double-layered BD-R (Blu-Ray Recordable), which max out at 50GB? BD-RE (Blu-ray Rewritable) might or might not be practical because nobody has produced a double-layer version, so they currently max out at 25GB. I'm not sure that any double-layer rewritable is possible... If it were technically feasable, wouldn't double-layer rewritable DVD (- or +R) have been available for some time? . Hello, from Albany, CA!... |
Cosmic_Ocean Send message Joined: 23 Dec 00 Posts: 3027 Credit: 13,516,867 RAC: 13 |
WEll if Arecibo goes dark, I guess we could change the focus of the project to distributing the work for NTPCkr? Linux laptop: record uptime: 1511d 20h 19m (ended due to the power brick giving-up) |
Josef W. Segur Send message Joined: 30 Oct 99 Posts: 4504 Credit: 1,414,761 RAC: 0 |
I noticed that the maximum data file size on the server is 50.20GB. If you could tell them to record slightly shorter file sizes, could you instead go to double-layered BD-R (Blu-Ray Recordable), which max out at 50GB? BD-RE (Blu-ray Rewritable) might or might not be practical because nobody has produced a double-layer version, so they currently max out at 25GB. The multibeam recorder at Arecibo doesn't record those file sizes, it produces a series of data blocks on a 500 GB or larger disk. Recording 14 full data channels plus the radar blanking gives a rate of over 18 MegaBytes/Second. When the disk is getting full another is started. The full disk is eventually shipped back to Berkeley, where the data is pulled off and divided into those 50.2 GB files. The initial configuration of the multibeam recorder used 300 GB tapes, but that form of removable media didn't work out. I don't know if there's an alternative removable media which might be reliable. The recorder was also designed to be able to send the data back immediately, that simply requires a connection from Puerto Rico which could pass about 20 MB/S of data at an affordable price. Joe |
Cosmic_Ocean Send message Joined: 23 Dec 00 Posts: 3027 Credit: 13,516,867 RAC: 13 |
I noticed that the maximum data file size on the server is 50.20GB. If you could tell them to record slightly shorter file sizes, could you instead go to double-layered BD-R (Blu-Ray Recordable), which max out at 50GB? BD-RE (Blu-ray Rewritable) might or might not be practical because nobody has produced a double-layer version, so they currently max out at 25GB. If I remember correctly from a very old tech news post, the 50gb size was picked because that was the file size limit for the offsite storage..either that, or it was convenient because of that size..or something. That memory is a little bit fuzzy. I do remember hearing something about why that size was chosen. Linux laptop: record uptime: 1511d 20h 19m (ended due to the power brick giving-up) |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 31014 Credit: 53,134,872 RAC: 32 |
Thanks for the update. Wish I had a solution, but with the strong possibility of Arecibo going dark I know spending money isn't in the cards. I don't think you will get an official answer, but here is what would happen. After the last data unit is crunched and validated, the data (on the science server) will be checked for likely candidates. Of those other telescope time will be requested for a follow up. Then they get busy and write the papers and publish. This will happen even if they get another data stream from another source for us to crunch. |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 31014 Credit: 53,134,872 RAC: 32 |
I noticed that the maximum data file size on the server is 50.20GB. If you could tell them to record slightly shorter file sizes, could you instead go to double-layered BD-R (Blu-Ray Recordable), which max out at 50GB?... More importantly can they record data as fast as the telescope generates it? I think they are actually ruled out because we have seven data streams being recorded at once. While being written they are like a tape and not random access like a hard disk. Then there is the cost issue. Even in bulk BD-R's are not cheap yet. A handful of them and you have the price of a SATA drive. I'm sure Eric knows all the storage options and chose SATA for an important reason. Unfortunate that the connectors have become an issue. Don't know if any hot swap enclosure manufacturer out there takes a SATA drive puts in on a carrier that uses an e-SATA to mate to the enclosure, but it sounds like that could be the solution. |
Cosmic_Ocean Send message Joined: 23 Dec 00 Posts: 3027 Credit: 13,516,867 RAC: 13 |
I noticed that the maximum data file size on the server is 50.20GB. If you could tell them to record slightly shorter file sizes, could you instead go to double-layered BD-R (Blu-Ray Recordable), which max out at 50GB?... I think from this point, there are two options. The 5-bay eSATA enclosure I've got is iStar-USA dAge540TL-ES. It uses bare drives (what a trayless design means). True this involves using the SATA connector repeatedly which is the current problem. The alternative is what I use at work (we have at least a thousand of these in both SATA and IDE), which is by CRU, and is the Dataport 5 (V) Series. You install the drive in the caddy, and then the contacts on the caddy and the frame are rated for 50,000 mating cycles. CDW has them for sale. Linux laptop: record uptime: 1511d 20h 19m (ended due to the power brick giving-up) |
Norwich Gadfly Send message Joined: 29 Dec 08 Posts: 100 Credit: 488,414 RAC: 0 |
Why is it necessary for the data from the telescope to be saved directly to the device used to transport the data to the lab ? Once a "tape" is full, it can be copied at leisure while the telescope is writing to another "tape". |
Richard Haselgrove Send message Joined: 4 Jul 99 Posts: 14679 Credit: 200,643,578 RAC: 874 |
Because the copying would have to be done at Arecibo, and SETI@home doesn't have any staff based there. AFAIK, SETI have a pretty limited agreement with Arecibo to supply power to the recorder, and manpower to swap disks, and that's about it. Everything else has to be automated, or it doesn't happen. When the new multibeam recorder was needed, SETI had to design and build it in their labs at Berkeley (you can't buy something like that off the shelf), and then travel to Arecibo themselves to install it. Any change to the recording/transporting procedure would mean new hardware built at Berkeley, another trip to Arecibo to install it, and a new legal agreement with the telescope operators. That sounds like a last resort to me. |
Norwich Gadfly Send message Joined: 29 Dec 08 Posts: 100 Credit: 488,414 RAC: 0 |
Thanks for the explanation ! |
.clair. Send message Joined: 4 Nov 04 Posts: 1300 Credit: 55,390,408 RAC: 69 |
I like the new layout and wording on the`tasks for user` pages, it better explains the state of the workunit, thanks. |
Sirius B Send message Joined: 26 Dec 00 Posts: 24913 Credit: 3,081,182 RAC: 7 |
With regards to enclosures, I have one that can be used, either as a usb or rj45 connection. Would these offset the sata problems? Safecom Network Attached Storage enclosure. |
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