Should We Ever Talk About JBODs
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@scottalanmiller said in Should We Ever Talk About JBODs:
@Tim_G said in Should We Ever Talk About JBODs:
@Tim_G said in Should We Ever Talk About JBODs:
Maybe a disk is to a RAID as a brick is to a house. A JBOD is to a RAID as a truck of bricks are to a house.
I say that because the word 'disk' is in JBOD. A bunch of disks. Not a single disk. A single disk can be a disk by itself... it could be a part of an existing raid, or it might not be. A JBOD is a bunch of disks. The definition of JBOD is that it's a bunch of disks, that are not yet part of a RAID, which also has the word 'disk' in it.
If you say a JBOD is the underlying foundation of a RAID... it's not. Yes, a RAID is made up of a bunch of disks. But to say you have a RAID on top of a JBOD... you are kind of saying you have a house built on top of a truck of bricks. Yes, you built it from a truck of bricks, but it's no longer a truck of bricks. Just like those disks are no longer a JBOD, now that they are RAIDED.
So in that case SS cannot use JBOD nor can RAID. Everything starts as JBOD and nothing ends as it. So never a time to use the term, right?
And JBOD is something you can never know about at the storage layer if you are using this definition. Even if you make JBOD and present JBOD to the next team or layer, their use of it would make it no longer JBOD.
SS requires JBOD. RAID requires JBOD, too.
I think JBOD term itself in the industry has been formed to mean an enclosure of a bunch of disks... such as a DAS enclosure you'd hook up to a server via an HBA.
Perhaps that's not technically correct, but for practical purposes, it works.
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@scottalanmiller said in Should We Ever Talk About JBODs:
@DustinB3403 said in Should We Ever Talk About JBODs:
As a term JBOD doesn't make a lot of sense, I agree. The term I think was meant more as marketing then a technical term.
I've literally never heard any vendor use the term in marketing, white papers, in person... nothing. I've never heard the term outside of SMB IT pros talking about... random things.
Hold the phone.. didn't MS use it for a bit while talking about Exchange?
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@Dashrender said in Should We Ever Talk About JBODs:
@scottalanmiller said in Should We Ever Talk About JBODs:
@DustinB3403 said in Should We Ever Talk About JBODs:
As a term JBOD doesn't make a lot of sense, I agree. The term I think was meant more as marketing then a technical term.
I've literally never heard any vendor use the term in marketing, white papers, in person... nothing. I've never heard the term outside of SMB IT pros talking about... random things.
Hold the phone.. didn't MS use it for a bit while talking about Exchange?
Really?
I've seen it used all over the place in official docs. Just a super quick search as an example: https://technet.microsoft.com/en-us/library/hh831739(v=ws.11).aspx
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@Tim_G said in Should We Ever Talk About JBODs:
@scottalanmiller said in Should We Ever Talk About JBODs:
@Tim_G said in Should We Ever Talk About JBODs:
@Tim_G said in Should We Ever Talk About JBODs:
Maybe a disk is to a RAID as a brick is to a house. A JBOD is to a RAID as a truck of bricks are to a house.
I say that because the word 'disk' is in JBOD. A bunch of disks. Not a single disk. A single disk can be a disk by itself... it could be a part of an existing raid, or it might not be. A JBOD is a bunch of disks. The definition of JBOD is that it's a bunch of disks, that are not yet part of a RAID, which also has the word 'disk' in it.
If you say a JBOD is the underlying foundation of a RAID... it's not. Yes, a RAID is made up of a bunch of disks. But to say you have a RAID on top of a JBOD... you are kind of saying you have a house built on top of a truck of bricks. Yes, you built it from a truck of bricks, but it's no longer a truck of bricks. Just like those disks are no longer a JBOD, now that they are RAIDED.
So in that case SS cannot use JBOD nor can RAID. Everything starts as JBOD and nothing ends as it. So never a time to use the term, right?
And JBOD is something you can never know about at the storage layer if you are using this definition. Even if you make JBOD and present JBOD to the next team or layer, their use of it would make it no longer JBOD.
SS requires JBOD. RAID requires JBOD, too.
I think JBOD term itself in the industry has been formed to mean an enclosure of a bunch of disks... such as a DAS enclosure you'd hook up to a server via an HBA.
Perhaps that's not technically correct, but for practical purposes, it works.
Yeah, everything requires JBOD, then it stops being JBOD
Hence the problem. It's all JBOD at some level or early on. And it's all not JBOD later. -
@Tim_G said in Should We Ever Talk About JBODs:
@Dashrender said in Should We Ever Talk About JBODs:
@scottalanmiller said in Should We Ever Talk About JBODs:
@DustinB3403 said in Should We Ever Talk About JBODs:
As a term JBOD doesn't make a lot of sense, I agree. The term I think was meant more as marketing then a technical term.
I've literally never heard any vendor use the term in marketing, white papers, in person... nothing. I've never heard the term outside of SMB IT pros talking about... random things.
Hold the phone.. didn't MS use it for a bit while talking about Exchange?
Really?
I've seen it used all over the place in official docs. Just a super quick search as an example: https://technet.microsoft.com/en-us/library/hh831739(v=ws.11).aspx
And look, it's used incorrectly. What does it even mean in Microsoft's world? They say "disks and JBODs" as if they are two different things. If a JBOD is not "just a bunch of disks" then Microsoft has made up a new meaning of the term. Where do they define it?
Maybe they mean "enclosure of disks" but then we can't say that anything requires a JBOD because by definition, nothing would know when it does or does not have one.
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Apparenty, JBODs in Microsoft's world are way, way more than we are normally thinking: "JBOD storage enclosures are designed with redundant hardware—such as JBOD controllers, SAS ports, and power supplies—to avoid a single point of failure if a part goes down."
So according to MS, only highly redundant enclosures are JBODs. So a totally new misuse of the term that's unique to them. And what is a "JBOD controller", another new term.
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I tend t agree with you Scott - JBOD has never really made sense to me. It has no safety or recoverability, so what's the point.
When I read about Exchange using it, I basically saw MS using it like Drobo with their Beyond RAID stuff, only MS was handling it transparently behind Exchange. Though I never real dug into it that much.
Though now I don't know that they actually applied any RAID type magic to the JBOD and instead relied upon DAG for their recoverability.
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@Dashrender said in Should We Ever Talk About JBODs:
I tend t agree with you Scott - JBOD has never really made sense to me. It has no safety or recoverability, so what's the point.
When I read about Exchange using it, I basically saw MS using it like Drobo with their Beyond RAID stuff, only MS was handling it transparently behind Exchange. Though I never real dug into it that much.
Though now I don't know that they actually applied any RAID type magic to the JBOD and instead relied upon DAG for their recoverability.
They use data protection, it's just higher in the stack. It's not RAID, but the equivalent is there. Same with SQL Server. They are never recommending that you use JBOD for any of those, not actual JBOD. MS is just using the term in a totally unique and made up way that doesn't match anyone else's definition and no one is, I don't think, 100% sure how MS is using it.
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This is what Microsoft considers a JBOD: https://www.windowsservercatalog.com/results.aspx?&bCatID=1645&cpID=0&avc=10&ava=0&avt=0&avq=0&OR=1&PGS=25
An enclosure of a bunch of disks: "...just-a-bunch-of-disks (JBOD) enclosure" as in the above link that they point to.
So a JBOD, is a specific object or product. Yes, the words themselves have a different meaning than when used as a whole.
For example, this is a JBOD: http://dataonstorage.com/dns-jbod-enclosure/dns-2608-4u-32-bay-12gbps-sas-enterprise-jbod-storage-enclosure.html
This is NOT a JBOD:
Going word-by-word, yes, the above is just a bunch of disks. For sure. That is what it is. But it's useless like that.
What a JBOD is in IT terms, is a JBOD enclosure specifically. When you refer to a JBOD, you are referring something like Microsoft links to or one of those DataON JBOD storage enclosures.
I think you are thinking too deep into it looking to pick it apart. Going in to it with the preconception of it being wrong will lead you to nitpicking.
If I were you, I would sum up the definition of what JBOD is supposed to mean. Not nitpick it apart to make it mean the literal pile of disks the individual words mean. I believe it is supposed to mean what I linked above: http://dataonstorage.com/dns-jbod-enclosure/dns-2608-4u-32-bay-12gbps-sas-enterprise-jbod-storage-enclosure.html. And I also believe that's what most IT Professionals think it means. Sure, you'll have the few who are just wrong, but the majority I'm talking about. Maybe not, but the people who deal with the things do.
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@Tim_G said in Should We Ever Talk About JBODs:
This is what Microsoft considers a JBOD: https://www.windowsservercatalog.com/results.aspx?&bCatID=1645&cpID=0&avc=10&ava=0&avt=0&avq=0&OR=1&PGS=25
An enclosure of a bunch of disks: "...just-a-bunch-of-disks (JBOD) enclosure" as in the above link that they point to.
That doesn't agree with their other document that I quoted.
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So JBOD just means a storage enclosure now? ug.. just another term for something we already had a term for?
JB /sigh going on here.
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@Tim_G said in Should We Ever Talk About JBODs:
Going word-by-word, yes, the above is just a bunch of disks. For sure. That is what it is. But it's useless like that.
What a JBOD is in IT terms, is a JBOD enclosure specifically. When you refer to a JBOD, you are referring something like Microsoft links to or one of those DataON JBOD storage enclosures.
But we have a term for that, too. A disk enclosure. Even in the MS working they have to say JBOD Enclosure. If JBOD means enclosure, then they are saying "enclosure enclosure" which would be a rack of enclosures or something. Clearly MS is not clear internally as to what it means. Is JBOD the disks or the enclosure? They go back and forth.
Which is my point. Microsoft is the best possible reference - if they can't figure it out, can't agree with themselves and don't even come close to agreeing with Wikipedia, common usage or common sense... obviously the term doesn't have a place in IT. There is simply never a time that using the term is meaningful or useful. It never clarifies and it never provides additional information. It is, at best, confusing and redundant.
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@Tim_G said in Should We Ever Talk About JBODs:
I think you are thinking too deep into it looking to pick it apart. Going in to it with the preconception of it being wrong will lead you to nitpicking.
Likewise, going in assuming that it has to be right will lead to overlooking the obvious problems. It's clear that we can't find any two sources that agree as to what it is. In this thread, everyone had a different - TOTALLY different, idea of what it is. Microsoft has at least three different ideas. SW had the same issue, everyone had a different idea of it with several that were not copied here. And then Wikipedia has the only one that matches the words.
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@Tim_G said in Should We Ever Talk About JBODs:
If I were you, I would sum up the definition of what JBOD is supposed to mean. Not nitpick it apart to make it mean the literal pile of disks the individual words mean. I believe it is supposed to mean what I linked above: http://dataonstorage.com/dns-jbod-enclosure/dns-2608-4u-32-bay-12gbps-sas-enterprise-jbod-storage-enclosure.html. And I also believe that's what most IT Professionals think it means. Sure, you'll have the few who are just wrong, but the majority I'm talking about. Maybe not, but the people who deal with the things do.
Right, but I don't agree, nor does Wikipedia nor the majority of the handful of people surveyed. See the problem? I think JBOD means exactly what it says and a JBOD enclosure means an enclosure of otherwise unassociated disks.
And starting form the point of "what do I think it should mean" leads me to "there is no use for this term." Since it is nothing but an unclear alternative to already existing, very clear terms.
If you look here and at MS and on SW, most IT pros don't agree with your "most" nor does Wikipedia. While it is possible that it is most, it's certainly not all and it's not "most" that we've found.
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@Tim_G said in Should We Ever Talk About JBODs:
I believe it is supposed to mean what I linked above: http://dataonstorage.com/dns-jbod-enclosure/dns-2608-4u-32-bay-12gbps-sas-enterprise-jbod-storage-enclosure.html.
But even that link doesn't agree with your definition. That link says it is a JBOD Enclosure, not a JBOD. Just like we have disks, and a disk enclosure. It's 100% in agreement with how I and Wikipedia have used the term, but not how MS is using it.
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@Tim_G said in Should We Ever Talk About JBODs:
The technical definition of JBOD are disks that haven't been RAIDed or anything yet.
See your definition here doesn't match how you are now using it. I agree here, JBODs are disks that haven't been RAIDed or anything yet. Which means JBOD = disks, just like the words say. No mention of enclosure.
A JBOD Enclosure is just another wording of "disk enclosure" by extension. And that appears to be how the manufacturers use it and makes total sense.
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@scottalanmiller said in Should We Ever Talk About JBODs:
A JBOD Enclosure is just another wording of "disk enclosure" by extension. And that appears to be how the manufacturers use it and makes total sense.
If by total sense you mean a bunch of marketing crap to sound cool to the unknown.. uhh... OK yeah, makes total sense. LOL
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^ was a total joke post for those who didn't know that.
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@scottalanmiller said in Should We Ever Talk About JBODs:
@Tim_G said in Should We Ever Talk About JBODs:
Going word-by-word, yes, the above is just a bunch of disks. For sure. That is what it is. But it's useless like that.
What a JBOD is in IT terms, is a JBOD enclosure specifically. When you refer to a JBOD, you are referring something like Microsoft links to or one of those DataON JBOD storage enclosures.
But we have a term for that, too. A disk enclosure. Even in the MS working they have to say JBOD Enclosure. If JBOD means enclosure, then they are saying "enclosure enclosure" which would be a rack of enclosures or something. Clearly MS is not clear internally as to what it means. Is JBOD the disks or the enclosure? They go back and forth.
Which is my point. Microsoft is the best possible reference - if they can't figure it out, can't agree with themselves and don't even come close to agreeing with Wikipedia, common usage or common sense... obviously the term doesn't have a place in IT. There is simply never a time that using the term is meaningful or useful. It never clarifies and it never provides additional information. It is, at best, confusing and redundant.
Microsoft is using the term "JBOD". They only add the word "enclosure" depending on the context. It appears that way to me anyways.
For example, "SAS connected JBODs that comply with Windows Certification requirements"
vs.
"These HBAs are connected to all JBOD enclosures in the file server cluster, and can’t have built-in RAID functionality."Example, "RAID adapters, if used, must have all RAID functionality disabled and must not obscure any attached devices, including enclosure services provided by an attached JBOD."
vs.
"Serial ATA (SATA) or Serial Attached SCSI (SAS) connected disks, optionally in a just-a-bunch-of-disks (JBOD) enclosure"Or here, where they use both in the same sentence! "Enough JBOD enclosures to tolerate an entire JBOD failing or becoming disconnected"
Every time in Microsoft documentation they use the word JBOD, it's used correctly that I've seen. It's used to mean one thing, always. It's never used to mean anything other than this: http://dataonstorage.com/dns-jbod-enclosure/dns-2608-4u-32-bay-12gbps-sas-enterprise-jbod-storage-enclosure.html
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@scottalanmiller
I'm familiar with JBOD as just a random collection of drives with no logical filter between them and the host.Now RAIN -- I have to admit to having never heard this term outside of weather. I'm not exactly a newb in the realm of computing, so I'm wondering which terminology silo it came from.
