Then what makes SCSI seem better?

Post #33,889 by Brandioch 3/30/02 10:45:06 PM Reply	Then what makes SCSI seem better? I'll echo Andrew's comments about CD burners. EIDE >REQUIRE< that they be on different controllers. I also SEEM to have better response/performance from SCSI hard drives in servers. If the components are the same, is it the controller that makes the difference? Not that I'm adverse to putting a dozen or so controllers in a box and running IDE.
Post #33,892 by folkert 3/30/02 11:22:21 PM Reply	The what! See [link\|http://z.iwethey.org/forums/render/content/show?contentid=33848\|Remodeling gone awry]. Just remember, IDE sucks with more than one device sharing the channel. That is why 3ware uses 4,8 and (soon to be released)12 IDE ports on a single card. The card support only ONE IDE drive per channel. So you say this is a down fall, well SCSI signalling is different, and able to handle multiple different speed devices on the same BUS. IDE can't. Just is that way. If you look at the link above, you see what I did for a company. Early numbers maybe indicating the only thing the SCSI setup has over the IDE setup, is better heat generation. As of right now this minute the transfers on the IDE "Logical Drive" are coming in at about 600-610MB/Sec, but I believe that is limited cause of the memory testing going on concurrently, along with a couple of kernel compiles at the same time. The SCSI "Logical Drive" is currently averaging about 550-780MB/sec depending on stuff staying in the (128MB) controller cache, I believe. Gonna switch over to a low-latency kernel and see what happens, some time tomorrow(easter). `greg, curley95@attbi.com -- REMEMBER ED CURRY!!! Keep software free. Oppose the CBDTPA. Kill S.2048 dead. [link\|http://www.eff.org/alerts/20020322_eff_cbdtpa_alert.html\|[link\|http://www.eff.org/alerts/20020322_eff_cbdtpa_alert.html\|http://www.eff.org/...a_alert.html]]`
Post #33,932 by Brandioch 3/31/02 3:24:08 PM Reply	Sounds good. The only things I need are: #1. It has to be as FAST as the SCSI stuff I work with today. #2. It has to do RAID 5. (preferably two RAID 5 arrays setup in a mirrored configuration (RAID 5+1)). #3. The drives have to be hot swappable. #4. It does all the above in hardware so the OS doesn't see anything but one big drive that it can boot off of it. #5. Lots of blinken lites. We've used a Snap! server before. Four drives (I think) in a RAID 5 array. It wasn't bad, but it was SLOW to back it up with ArcServe. The NetWare and Windows boxes would zip right along. This one would CRAWL at a few megs a minute. Then, one day, it just decided to forget its array configuration and lose all the data. The speed was the problem for us. It was okay writing to, but a dog getting the stuff off in mass quantities. I'm sure there was a configration setting that would solve this. Whether it was available to us end-users is another question. Now, I'm thinking about turning it into an MP3 server. Just to hammer on it and see if I can make it fail again. I'm going to have to try the 3ware stuff in my toy servers soon. Thanks.
Post #33,934 by folkert 3/31/02 4:27:47 PM Reply	Well, it all depends... #1. It has to be as FAST as the SCSI stuff I work with today. You saw my numbers so far... They are still holding out. Gotcha covered there. #2. It has to do RAID 5. (preferably two RAID 5 arrays setup in a mirrored configuration (RAID 5+1)). It does do RAID-0 RAID-1 RAID-5 RAID-10 with Hot-Spare. Gotcha sort of covered here too. #3. The drives have to be hot swappable. IDE Hot-swap cages are coming out of the wood work these days. The one 3Ware actually sells works very well, but one has 3 slots per cage (1 full-height slot). The cards support hot-swap as well. Gotcha under the blanket now too. #4. It does all the above in hardware so the OS doesn't see anything but one big drive that it can boot off of it. Offers JBOD, RAID0, RAID1, RAID5, RAID10 and I think Linear array all behind the smoke and mirrors so the OS just addresses one big dumb Drive, and can boot from it. Blanket seems to cover that. #5. Lots of blinken lites. 1 Blinking light per IDE channel, plus 4 for status... just on the controller itself. Now as for thier H/S IDE cage, 2 LED per drive, one activity, one powered/status(tri-mode). Now hows that for lights. Been sleeping comfortably now I see. Now the reason, I setup my things the way I did, I like to be able to replace the "system" in case of a catastrophic failure on the machine. Then just move the controller/subsystem to a "new" machine. The only question I have for you, What do you really need RAID5+1 for??? Speed? or diaster recovery/redundancy? Speed, ain't no big thing. Remember this IDE card only has 1 drive per channel. (ATA-133 theoretically gives you 133MBytes/sec * 8 Channels) SCSI has multiple per channel. You only get 160MBytes once per channel. Diaster recovery/Redundancy? Well, here is basically what I am going to say. Unless you have Fiber Storage at least 2KM from your primary Data you are hosed anyways. Setup you raid-5 arrays with Hot-Spare(s). Even setup you Mirrors with Hot-Spares. Setup all your fault tolerant arrays with hot spares, and alot of your concerns about SCSI or IDE go away. Oh, one more thing(I hope just 1 more), backing up a SNAP! server or ANY target without a TSA is a bad thing. Make things crawl period with ANY backup solution. Even Tivoli Storage Manage(TSM) (formerly Ad-Star Storage Manager or ADSM) doesna worky well without a Target Service Agent on the machine the Server itself runs on. `greg, curley95@attbi.com -- REMEMBER ED CURRY!!! Keep software free. Oppose the CBDTPA. Kill S.2048 dead. [link\|http://www.eff.org/alerts/20020322_eff_cbdtpa_alert.html\|[link\|http://www.eff.org/alerts/20020322_eff_cbdtpa_alert.html\|http://www.eff.org/...a_alert.html]]`
Post #33,954 by Ashton 3/31/02 10:26:14 PM Reply	Hey there, Greg It seems as if that Tek 454A went to a good place - it's still the best for lo-level (2 mV/div!), super-sharp trace sleuthing at the 150 MHz level = er reduced BW at That low a level. Now whatcha need for the above fancy stuff! at near 600 MHz BW* and whatever 7000-series plug-ins turn you on (like mV at 100 MHz differential input? check out those r/w heads Directly..): * "400 MHz nom." measured = 600; now That's conservative.. is a Tek 7854, 4-plug-in mainframe. I gots an extra! It provides pure analog == Real, not that digital-approximation stuff BUT: also digital storage and manipulation of the data. This can be saved indefinitely via just a simple PS keeping the mem. alive with scope off. Iterate n-times and you can see the glitches too. And the number of illuminated PBs and fancy delay switching lights.. warm cockles of heart. Yeh it's bigger, but it's beautiful and has a keyboard for programming some rather clever automatic tests: the honesty of analog + digital 'convenience'. (I was checking rise-time with a 50 pSec generator: clear sharp traces even at 0.5 nSec/DIV, unmagnified) Anyway, the world is crazy enough that, such lab grade equipment is now ridiculously cheap. Til all the good ones are gone. 'Course you may be too busy using this stuff to test it ;-) Ashton
Post #33,958 by a6l6e6x 3/31/02 10:44:51 PM Reply	OT: Tek scopes Ashton, you are terrible. You had to remind me of a day of joy when a Tek 545-B with dual trace and delayed sweep arrived for my use. What a quality work horse that was! Yes, I know it's a different scope, but the model numbers are a hair away in memory. Alex "Never express yourself more clearly than you think." -- Neils Bohr (1885-1962)
Post #34,077 by Ashton 4/1/02 8:18:26 PM Reply	Yeah.. imagine finding Art in a lab. I remember too, when the first 545 [no -B] arrived at the electron synchrotron - replacing a 514 AD IIRC (?) All those ceramic terminal strips, anodised aluminium - and as close to perfection as a manufactured product might get. We just stood around looking at it, with the covers off. (What a great living room display for the Upscale folk - even today - leaving off the covers! Especially late at night = foot warmer too) As doubtless you are aware, quite a few are still around and in (or restored to) original condition. Pity that 500ish watts is just a bit much and 30ish MHz a bit little :( But with sampling plug-ins, BW is still respectable; not a few 1L4 (?) spectrum analyzers are still being used too. I have a 564B storage scope with a Nelson-Ross audio spectrum analyzer plug-in. Gotta find an audio type to get this one. Clean as new - and the -B mainframe was all solid state (though the Ross unit ain't.) Anyway.. Tek ain't Tek anymore - just as HP has become a commodity reseller of $30 ink cartridges at 500% profit. Still, I've culled pristine examples of the clever Sony-Tek small scopes, like the small 35 MHz 335; another model of same size at 5 MHz / w DVM, etc. These peddled for >$3k towards the end of their run == now just hundreds, and some like new. Someday soon, people won't believe an actual "Corporation" was ever motivated to build such quality. {sigh} Quality - look for that in your local museum. Ashton hoping sometime to steal a 2467-B "Bright-eye" scope, just for the hell of its impossible complexity / simple operation.
Post #34,088 by a6l6e6x 4/1/02 10:51:18 PM Reply	Re: Yeah.. imagine finding Art in a lab. Did you ever note the little cartoons on the schematics in the manual? Or, the small roll of silver solder inside the case for an unlikely repair? Alex "Never express yourself more clearly than you think." -- Neils Bohr (1885-1962)
Post #34,114 by Ashton 4/2/02 12:39:05 AM Reply	Yup.. Loved the skier.. down a delay-line IIRC !! The little rolls of, technically "3% silver-bearing", not really silver-solder - so as not to cause the 'fritted silver' on the strips to come loose with repeated tin-lead soldering. Perfectionist stuff, and on its own white ceramic-like bobbin! But what the New-Tek is like: I burned up the First e- thing ever (well, almost) on a #$#@% 2430 digital scope: seems that it May Not be operated out of the case w/o "an additional air supply". Now there were labels of usual dummy kind.. CAUTION Glass CRT under high vacuum* and the like.. but only (later when it came) in the manual ~ p.45 was a little note about this peculiarity. And NO LABEL inside the case. D'Oh. Really pissed me off because I was able to cure an error message about a particular part by forcing a re-cal; scope would have been OK. But then I recalled.. in space, nobody can hear you scream.. Grumble, piss, moan
Post #33,994 by folkert 4/1/02 12:14:08 PM Reply	Hey there, Ashton Just to let you know, the 454 is firmly mounted in my workbench I finally got around to making. It's where I make all my junk come to life.... MUHAHAHAHA!!!! Believe it or not, I haven't even come close to running out of BW on the 454A. It works just fine. I actually had to replace a couple of Electrolytics in the Power Supply last month... It was acting funny... perfectly good one minute... wandering all over the place the next. So, I hooked up my trusty "self-made" fet VOM I built from scratch (using Plywood as the face) and saw voltage rising and dropping...rising and dropping right after the filters on the PS. Started looking at the components to see if they all had thier magic smoke in them still, sure enough 2 Caps had split covers. Apparently boiled at some point not to long ago. But put expensive replacements in... voila she good as new, No? BTW, you should really look at the new "synthetic" Electrolyte companies are using in "premium" Caps. It smells terrible, even compared to arsenic based electrolyte. But, it is black and gooey. Supposedly has 5-10 times the insulating and cooling capability of standard electrolyte. Same size caps have high capacitance and higher volage ratings. L8RZ. `greg, curley95@attbi.com -- REMEMBER ED CURRY!!! Keep software free. Oppose the CBDTPA. Kill S.2048 dead. [link\|http://www.eff.org/alerts/20020322_eff_cbdtpa_alert.html\|[link\|http://www.eff.org/alerts/20020322_eff_cbdtpa_alert.html\|http://www.eff.org/...a_alert.html]]`
Post #34,072 by Ashton 4/1/02 7:56:30 PM Reply	Good sleuthing and thanks for the tip on someone finally looking for insulation AND heat transfer (D'Oh..) I bought an Aussie designed clever (and small) ESR measuring device for that service (of course when the thing is split.. well, that's lucky). 2 LEDs read out the ESR; a clever IC-design, I thought. As you know, an ohms check will tell shorted, but a bridge won't know about the series ohms. Anyway, have a few (!) 485s and I don't want to have to unsolder / substitute all those barely accessible thingies. The meter sits there waiting for me to attack the pile :( Wanna fix some switching supplies accompanied by rest of 485? As to 454 BW being adequate.. I thought you wanted to find Truth, not just an approximation! :-\ufffd

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