Talk:RAID

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Former good article nominee RAID was a Engineering and technology good articles nominee, but did not meet the good article criteria at the time. There are suggestions below for improving the article. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.
May 22, 2006 Good article nominee Not listed
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Merger proposal[edit]

I propose that Standard RAID levels be merged into RAID. I think that the content in the Standard RAID levels article can easily be explained in the context of RAID, if it is not already. I cannot justify the duplication of effort when it comes to listing RAID levels. One example is the recent addition of a table of levels to the Standard RAID levels article, when a much more established table of differences already exists in the RAID article. Listing basic RAID levels in two places is redundant, so I removed it. I felt bad when doing so because an editor worked hard on the new table, having not seen the existing one. It's easy to see how one would land on Standard RAID levels and assume they are on Wikipedia's one-and-only RAID article. – voidxor (talk | contrib) 06:49, 23 January 2014 (UTC)

  • Oppose: From one side, that totally makes sense, as that way some content would be deduplicated. Though, if we do that, then merging Nested RAID levels and Non-standard RAID levels is also on its way, what would simply make RAID article too large. Also, there's more room for improvements to the Standard RAID levels article, in form of more content to be added, what additionally supports the counterargument of RAID article becoming too large. — Dsimic (talk) 14:53, 23 January 2014 (UTC)
    I disagree that this merge would be a gateway to merge Nested RAID levels and Non-standard RAID levels; those topics aren't nearly as duplicated on RAID as the standard levels. Also, while your recent edits to RAID help to clarify that it is not the authoritative article on the levels, perhaps you should have waited until this discussion was closed before you changed the status quo! – voidxor (talk | contrib) 06:48, 24 January 2014 (UTC)
    I apologize, doing that edit was too much of "going ahead" from my side. Sorry! :( At least, I hope you agree that it made the layout of RAID article much cleaner.
    How about, maybe, a different approach – moving the content of RAID § Comparison section into the Standard RAID levels article? That would be another approach to deduplication of the content, while keeping (and improving) current relation between these four articles. Also, we could add a hatnote to the "Standard RAID levels" article (and to "Nested RAID levels" and "Non-standard RAID levels" as well), pointing out the existence of an important "umbrella" article to anyone landing there.
    Another reason behind opposing your proposal is that the merge would make "Nested RAID levels" and "Non-standard RAID levels" articles (and their summary sections) visibly much less valuable, thus more likely to be skipped by the readers. On the other hand, if we move the "Comparison" section as I just proposed, the "umbrella" article would provide an equal treatment to all categories of RAID configurations, achieving the content deduplication at the same time.
    Thoughts? Once again, I apologize for running too fast. — Dsimic (talk) 19:44, 24 January 2014 (UTC)
    I agree that your edits made it cleaner (which is normally a good thing), but I hope it does not affect the balance of this debate. Otherwise, apology accepted. Relocating the Comparison section into the Standard RAID levels article is another option for voters, but I am the nominator and thus recuse myself from commenting on it. Again, I would not worry about Nested RAID levels and Non-standard RAID levels right now as the majority of readers are here for levels 0–6. – voidxor (talk | contrib) 07:01, 25 January 2014 (UTC)
    Thank you. Let's see what the other editors are going to say. — Dsimic (talk) 17:18, 25 January 2014 (UTC)
  • Oppose: This is used by people in the workplace who want a quick reference. It works well and I refer to it 2 times a week. — Preceding unsigned comment added by Lkshoe (talkcontribs) 17:01, 14 February 2014 (UTC)
    This discussion is debating whether the information from both articles should be merged into one; nobody is suggesting deleting the reference information. – voidxor (talk | contrib) 00:24, 20 April 2014 (UTC)
  • The article's overly-long as it is; arguably more of it should be split to sub-articles. Chris Cunningham (user:thumperward) (talk) 13:06, 8 April 2014 (UTC)

Justify Write Performance Claims in Table for RAID levels 4,5 and 6[edit]

The table claims that the write performance for RAID levels 4,5, and 6 are (n-1)x, (n-1)x, and (n-2)x, respectively. presumably n is the number of disks in the set and x is the write performance in IOPS of one such disk.

These claims are contrary to industry norms, which are x, nx/4, nx/6, respectively in the above list.

The article should provide a reference for the claims or they should be removed. — Preceding unsigned comment added by 168.159.213.208 (talk) 17:31, 16 April 2014 (UTC)

Yes check.svg Done: I have tagged these {{Citation needed}}. Hopefully an expert can revamp the expressions. Thank you for noticing it. – voidxor (talk | contrib) 05:07, 17 April 2014 (UTC)

"Data is" vs. "data are"[edit]

I undid Dsimic's last edit, where several instances of "data is" were again changed to "data are". Numerous editors keep editing this article to change these back to use the singular verb form, in what can only be described as edit warring. Unlike traditional warring, though, I've observed Dsimic versus the world instead of just one editor.

While I agree with Dsimic that the plural Latin nouns usually end in "a" and single Latin nouns in "um", Wiktionary offers a very insightful a third possibility. Basically, "data" can also be used as an uncountable noun—which is the norm in computing contexts like RAID. Surely that's because individual bits number in the trillions in today's machines and thus counting becomes a vain exercise. Similarly, water is made up of individual molecules but "a glass of waters" is poor grammar. I believe this to be why the vernacular supports the singular form, and why we should stick with it here. – voidxor (talk | contrib) 05:40, 14 June 2014 (UTC)

Hello there! I'm glad this is discussed, as "data are" sounds awkward no matter how correct (or not) it is. I'm perfectly fine with using "data" as an uncountable noun, and "data is" sounds much better to me. At least now I have a place to point other editors to once "data vs. datum" is raised again. :) — Dsimic (talk | contribs) 05:53, 14 June 2014 (UTC)
Not sure it will be a good place to point people to if you want "data is", since Voidxor's water example is going to convince people that supporters of "data is" can't think straight - "water" isn't the plural "molecule" abd besides no-one is going to talk about "a glass of molecules", but "data" is the plural of "datum"; it some contexts "data" is non-countable, in other contexts it isn't - probably it in most contexts it is, but to insist that it is non-countable in every context is precisely as silly a piece of pedantry as to instist that it is never non-countable. Michealt (talk) 16:16, 22 August 2014 (UTC)
Hello! Well, quite frankly, I'm a bit tired regarding "data is" vs. "data are", but—in the domain of Wikipedia articles, of course—an article should be fine as long as "data" is used consistently either as a countable or as an uncountable noun. — Dsimic (talk | contribs) 10:29, 25 August 2014 (UTC)
I agree with Dsimic; both are correct. The most important thing is that we're consistent. With that said, we should probably go with the vernacular—which appears to be the uncountable "data is" according to the edit history. – voidxor (talk | contrib) 05:25, 28 August 2014 (UTC)

Reliable single disks[edit]

A recent edit by Snori describes super-expensive SLED devices as “super-reliable” and the smaller, less expensive disks as “comparability unreliable”. That's not actually true, and I think it skews the description of the basic idea behind RAID.

  1. No one in 1987 thought the reliability of disk storage was a big problem. Although rotating disks, as moving parts, are more likely to wear out under normal use than purely electronic parts, that failure rate was still not very high.
  2. The original RAID paper by Patterson et al. cites about the same mean-time-to-failure rating for all of the disk drives mentioned, tens of thousands of hours of operation; in fact, the biggest-and-most-expensive mainframe disk (IBM 3380) and the smallest-and-least-expensive PC disk (Conner CP 3100) have exactly the same MTTF rating (30,000 hours).
  3. The emphasis on redundancy in RAID is because the overall reliability of an array drops by a factor of the number of drives involved. One small drive may have a MTTF of three or four years, but an array of 100 small drives might be expected to have a drive failure within two weeks. That's why redundancy was necessary, not because the individual drives were unreliable.

The leading motiviation to develop RAID was the higher performance which could be realized; associated benefits include larger and more flexible storage capacity, and reductions in equipment cost, size, and power consumption. Single disk reliability wasn't a big factor.  Unician   07:52, 1 September 2014 (UTC)

Well spotted! I suspect that they *suspected* that the inexpensive drives were less reliable (despite having the same stated MTTF figures), but the key issue re of an array of inexpensive disks is not that the drives themselves are less reliable, but that the array *itself* is less and less reliable the more drives it contains.Snori (talk) 01:53, 2 September 2014 (UTC)