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Post #33,100
by folkert
Picture of folkert
3/21/02 11:05:09 PM
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New Then why do we never here about...
SSA... huh?

Current revisions of SSA is extremely fast, Extremely reliable... matter of fact IBM uses them in thier Enterprise Storage Server (ESS - Shark).

Lets assume that there are significant reasons why IBM bucks the trends. Lets grant that IBM is all knowledgeable. Lets just wonder WHY SSA isn't as popular in PC servers as they are in RS/6000s.

In my extremely NON-Humble Opinion, SSA drives with SSA Raid controllers are Far and Wide the most reliable, fastest, scalable, easy to service, easy to make work, self diagnosing, points you to the problem, SETUP in all the world for Storage.

I can remove half the wires connecting the drives... as long as 1 remains connected between all of them SOMEHOW, they are all still available. They have zero degradation in performance in that situation, SSA RAID uses can make SCSI raid pale in comparison (even the mighty Mylex controllers IBM makes do too)

So explain to me people choose SCSI over SSA. Based upon you arguements SSA would be the ultimate.... PERIOD.

I'll tell you why... everyone has been brainwashed into thinking SCSI is BEST, IDE SUCKS anything else is "esoteric". SSA can sometimes be as much as 200%-600% more expensive than even the fastest SCSI.

I have gotten IDE RAID to work as well as SCSI RAID, including failure handling.

Some may indicate 3ware having problems, company has some developments coming down the pike that may surprise some of us. They are going to be gaining ground.

Now I agree earlier products from 3ware were/are buggy. But they have updated firmware for them... but component failure can't be fixed...

Oh well the question remains:

Why is SSA not as widely used as it should be?
greg, curley95@attbi.com -- REMEMBER ED CURRY!!!
In 2002, everyone will discover that everyone else is using linux. ** Linux: Good, fast AND cheap. ** Failure is not an option: It comes bundled with Windows. ** "Two rules to success in life: 1. Don't tell people everything you know." - Sassan Tat
Post #33,105
by Andrew Grygus
Picture of Andrew Grygus
3/22/02 12:06:45 AM
Reply
New Could be a bunch of reasons:
  • Ownership of IP (Intellectual Property) may restrict the number of vendors. Cost of licensing IP may make alternative vendors uncompetitive, so they don't enter the market. Single source is not wise in most (but not all) cases.
  • Cost may be beyond the point of diminishing returns for the majority of applications, just as the cost of SCSI is beyond the point of diminishing returns for most desktop PCs, but priced just right for midrange servers.
  • Lateness to market may make marketing cost to achieve economical volume too high, limiting the product to only the highest end market.
Products are designed for particular markets. IDE was designed very deliberately to reduce cost in volume production. Put the controller on the device, and make it a simple controller. SCSI was designed for greater flexibility and better performance. SSA was designed for very high end systems.

You can put 2 IDE devices on a cable, 16 SCSI devices. Even with just two, IDE devices don't share the cable very well. Hell, when I put a fast CD writer and a CD-ROM in the same machine I have to put them on separate IDE cables or I get underruns making copies, and CDs aren't really all that fast. I don't have that problem with SCSI.

True, newer IDE drives outperform older SCSI drives (at least if there's only one IDE drive on the cable), but SCSI is a moving target. Soon we will have Serial IDE which will solve the "2 per cable" limit, allow longer cables and greatly improve data transfer speed, but Serial SCSI has already been in development for quite some time and will be there for the more demanding markets.

Right now, high performance IDE is operating system dependent because of the special drivers needed. SCSI isn't. You can get high performance out of SCSI even on OS/2. I seriously doubt I could get SSA to work at all with the small business servers I build.

True, many SCSI drives are mechanically the same as equivalent IDE drives except for the control circuitry, but many aren't. Different SCSI drives are targeted to different markets. Right now IDE doesn't have that differentiation - it's all aimed at the lowest price market.

Trying to force any of these devices into the others' markets is not going to work well.
[link|http://www.aaxnet.com|AAx]
Post #33,110
by tonytib
3/22/02 1:18:29 AM
Reply
New Politics, IIRC
SSA was IBM's equivalent to FC-AL, and it lost out during standardization wars, IIRC. So a number of people use FC-AL, notably Sun, and FC-AL drives frequently appear on the surplus market (I don't believe I've ever seen an SSA drive) and even at Fry's occasionally, but only IBM uses SSA.

I don't know enough to compare FC-AL and SSA, so don't ask.

My internal knowledge of hard drive parts is based on the parts I've seen, mainly HSA's. Thus, my quality comments were based on the mechanical quality of the parts I've seen (view from inside), not on interface abilities, reliability, etc. Although I've picked up a fair amount of general knowledge (e.g. from IDEMA magazine, DiskCon, customers, etc), I'm not a hard drive designer. OTOH, I'm pretty sure, for example, that the Seagate SCSI engineers don't know much about the Seagate IDE drives (with the possible exception of the IDE Barracuda models if they share the same hardware).

My interests in RAID are unrelated to my work. I'm interested in RAID 5 controllers for home (maybe if the economy picks up) and small business. SSA and FC-AL are too pricey. IDE is a possibility, but I'll have to see a lot of good comments (e.g. on StorageReview.com) before I'll trust 3-ware. Promise and Adaptec are also possibilities. As I said before, I'm tired of PC stuff that half works. BTW, the Mylex SCSI RAID boards appear to be about the same price as the 3-ware IDE controllers.

As far as future greatness goes, well, my standard answer is: "I'll believe it when I can see it at Fry's". A lot of products (not just from MS) never make it out of the vapor (Linear Technologies, for example, had an analog chip that they had spec sheets for, advertised, and engineers started to design with -- but the chip never made it to production. So, a common EE rule is "If it's not in the DigiKey catalog, don't use it.")

Tony
     3Ware RAID: add replacement drive to degraded array - (kmself) - (36) - March 15, 2002, 02:16:52 AM EST
         Sounds like a card not drive problem to me. - (Another Scott) - (35) - March 15, 2002, 07:53:20 AM EST
             Also-check the signal cable to the "bad" drive.Intermittent? -NT - (Another Scott) - March 15, 2002, 08:36:03 AM EST
             Suspect you're right - (kmself) - March 15, 2002, 02:12:59 PM EST
             JBOD v. RAID on new disk insertion - (kmself) - (32) - March 15, 2002, 04:56:43 PM EST
                 Re: JBOD v. RAID on new disk insertion - (morganek) - (31) - March 16, 2002, 01:50:55 PM EST
                     Following procedure...confirms bad card - (kmself) - (30) - March 17, 2002, 04:14:22 AM EST
                         Re: SCSI. - (a6l6e6x) - (29) - March 17, 2002, 04:05:17 PM EST
                             IDE RAID - (Andrew Grygus) - (28) - March 17, 2002, 05:04:34 PM EST
                                 Interesting - (kmself) - (27) - March 17, 2002, 11:50:19 PM EST
                                     Have you guys seen the discussion on IBM's 120GXP 10 hr/day? - (tonytib) - (26) - March 18, 2002, 01:30:27 AM EST
                                         Heard about it, yeah -NT - (kmself) - March 18, 2002, 04:09:26 AM EST
                                         Components - (Andrew Grygus) - (3) - March 18, 2002, 11:00:45 AM EST
                                             Thanks -NT - (tonytib) - March 18, 2002, 02:43:02 PM EST
                                             IDE, SCSI, and change - (kmself) - (1) - March 20, 2002, 09:19:40 PM EST
                                                 SCSI is better, but not always - (tonytib) - March 20, 2002, 09:32:11 PM EST
                                         Re: IBM's 120GXP only 10 hr/day. - (a6l6e6x) - (20) - March 19, 2002, 11:04:16 PM EST
                                             But they won't guarentee it for >3 years - (tonytib) - (19) - March 20, 2002, 08:01:20 PM EST
                                                 No disagreement from here. -NT - (a6l6e6x) - March 20, 2002, 08:57:25 PM EST
                                                 Highly erratic - (Andrew Grygus) - (1) - March 21, 2002, 12:17:57 AM EST
                                                     I especially love that last comment! -NT - (tonytib) - March 21, 2002, 11:28:38 AM EST
                                                 Interesting.... Very interesting... [RANT] not just at Tony - (folkert) - (15) - March 21, 2002, 09:15:46 PM EST
                                                     Greg, I've been looking at actuators for six years now - (tonytib) - (3) - March 21, 2002, 09:46:09 PM EST
                                                         Then why do we never here about... - (folkert) - (2) - March 21, 2002, 11:05:09 PM EST
                                                             Could be a bunch of reasons: - (Andrew Grygus) - March 22, 2002, 12:06:45 AM EST
                                                             Politics, IIRC - (tonytib) - March 22, 2002, 01:18:29 AM EST
                                                     Then what makes SCSI seem better? - (Brandioch) - (10) - March 30, 2002, 10:45:06 PM EST
                                                         The what! - (folkert) - (9) - March 30, 2002, 11:22:21 PM EST
                                                             Sounds good. - (Brandioch) - (8) - March 31, 2002, 03:24:08 PM EST
                                                                 Well, it all depends... - (folkert) - (7) - March 31, 2002, 04:27:47 PM EST
                                                                     Hey there, Greg - (Ashton) - (6) - March 31, 2002, 10:26:14 PM EST
                                                                         OT: Tek scopes - (a6l6e6x) - (3) - March 31, 2002, 10:44:51 PM EST
                                                                             Yeah.. imagine finding Art in a lab. - (Ashton) - (2) - April 1, 2002, 08:18:26 PM EST
                                                                                 Re: Yeah.. imagine finding Art in a lab. - (a6l6e6x) - (1) - April 1, 2002, 10:51:18 PM EST
                                                                                     Yup.. - (Ashton) - April 2, 2002, 12:39:05 AM EST
                                                                         Hey there, Ashton - (folkert) - (1) - April 1, 2002, 12:14:08 PM EST
                                                                             Good sleuthing and thanks for the tip - (Ashton) - April 1, 2002, 07:56:30 PM EST

I let her go after 4 hours, told her why, so she blamed me personally for ruining this country.
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