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Mark Minasi
Chief cook and bottle washer
USA
10658 Posts
Status: offline |
 Posted - 07/12/2012 : 2:24:12 PM
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Hi all --
I'm doing more iSCSI (big surprise, it's no secret I'm doing 2012, right?) and it's all fun, but I don't get what's going on with the iSCSI names.
So I create some LUN (oh, sorry, we call them "iSCSI virtual disks" or something like that in 2012) on a server ("target") and the client ("initiator") then hooks up to that LUN via its iSCSI Qualified Name or IQN that looks something like
iqn.dateyougotyourdomain.domainnamebackwards[:optionaldescriptivestuff]
Thus, if my network had a LUN for storing the newsletter database on minasi.com, a domain that I've owned since 29 December 1997, I'd give it an IQN like
iqn.1997-12.com.minasi:newsletterLUN
As far as I can see, I assign that IQN to the SAN device holding the LUN, and when configuring the initiator, I punch in the IQN to hook 'em up. (I've gleaned this from RFC 3720/3721 but might have missed something, please correct me if I'm wrong.) You can also give these odd-looking names "aliases," more human-sounding names.
What I don't get is... what good is this?
It doesn't identify the machine acting as the target.
There doesn't seem to be by default any kind of central DNS-ish server, making it useless for target discovery.
So what real purpose does it serve? After all, I assume that most iSCSI targets are only available within an intranet, rather than accessible over the public Internet. I'd have assumed that there'd be some central location for aliases in an organization that would then resolve to the node IP address etc on the iSCSI target, but as far as I can see 2012 doesn't even let you GIVE a target an alias, so clearly that can't be a very useful tool.
I'd love any insight and pointers, and apologies if I've missed something obvious. Thanks!
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Mark
tweetin' at mminasi |
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chamezzzz
Honorable But Hopeless Addict
United Kingdom
2298 Posts
Status: offline |
Posted - 07/13/2012 : 04:54:31 AM
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Is the answer not there in section 3.2.6 Mark?
http://tools.ietf.org/html/rfc3720#section-3.2.6
iSCSI names must be unique within the operational domain of the end
user. However, because the operational domain of an IP network is
potentially worldwide, the iSCSI name formats are architected to be
worldwide unique.
Emphasis on potentially
Regards |
James |
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Mark Minasi
Chief cook and bottle washer
USA
10658 Posts
Status: offline |
Posted - 07/13/2012 : 2:40:41 PM
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| It just seems like more busy work... it doesn't make my life as admin any easier, just gives me more to do. |
Mark
tweetin' at mminasi |
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chamezzzz
Honorable But Hopeless Addict
United Kingdom
2298 Posts
Status: offline |
Posted - 07/13/2012 : 3:14:08 PM
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Yes, and I am not sure if Alias is even implemented in Microsoft 2008/2010 server iSCSI?
I have only used iSCSI with vSphere but I do not use the Alias option.
I add even more work to myself by only using Static Discovery, I document this and I know what Hosts are pointing at what disk. But I am a small shop with one iSCSI SAN.
Until your post I had not even thought about the similarity with DNS.
Greg Shields discusses Hyper-V and iSCSI here
http://nexus.realtimepublishers.com/sgais.php
How do other people manage large iSCSI implementations? |
James |
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Mark Minasi
Chief cook and bottle washer
USA
10658 Posts
Status: offline |
Posted - 07/13/2012 : 5:46:10 PM
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| Yeah, where IS Smirnov when we need him?<g> |
Mark
tweetin' at mminasi |
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wobble_wobble
Honorable But Hopeless Addict
Ireland
4517 Posts
Status: offline |
Posted - 07/14/2012 : 05:24:08 AM
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If I buy your company, one of the things I will not have to worry about 99% of the time is that one of your iSCSI addresses will not overlap.
That is one of the reasons I believe
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Joe
After everything that has happened during the month of Jan 07, I do believe that pigs fly backwards!
http://whatismyv6.com/ |
Edited by - wobble_wobble on 07/14/2012 05:25:04 AM |
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Mark Minasi
Chief cook and bottle washer
USA
10658 Posts
Status: offline |
Posted - 07/14/2012 : 10:12:43 AM
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| Oh, yes, I see that... it just didn't seem that important compared to facilitating server discovery. Thanks! |
Mark
tweetin' at mminasi |
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cj_berlin
Honorable But Hopeless Addict
Germany
3964 Posts
Status: offline |
Posted - 07/14/2012 : 11:20:27 AM
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quote:
Originally posted by Mark Minasi
Yeah, where IS Smirnov when we need him?<g>
On vacation 
My take on the IQNs is like this: In simple topologies like 2 hosts accessing one storage, IQNs aren't worth their length in bytes. In a complex multipathing scenario, however, zoning by IP can sometimes be troublesome or even impossible: first and foremost, you need to maintain multiple IPs for a single initiator (or target, for that matter - depends on where and how you zone), and then you should always consider the possibility of the initiators' IPs being even dynamic. If you have a SAN that can zone by IQN and make use of that, you needn't worry about the IPs involved.
HTH |
Evgenij Smirnov
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Mark Minasi
Chief cook and bottle washer
USA
10658 Posts
Status: offline |
Posted - 07/16/2012 : 10:14:56 PM
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Thank you, good sir. But, again, why is there no central directory of IQNs? Why is there no help for client systems to find targets?
I hope you're vacating somewhere fun.<g> |
Mark
tweetin' at mminasi |
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cj_berlin
Honorable But Hopeless Addict
Germany
3964 Posts
Status: offline |
Posted - 07/17/2012 : 07:24:53 AM
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quote:
Originally posted by Mark Minasi
Thank you, good sir. But, again, why is there no central directory of IQNs? Why is there no help for client systems to find targets?
... but there is: http://en.wikipedia.org/wiki/Internet_Storage_Name_Service |
Evgenij Smirnov
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Mark Minasi
Chief cook and bottle washer
USA
10658 Posts
Status: offline |
Posted - 07/19/2012 : 07:21:35 AM
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Hi Evgenij --
Sorry, should have been clearer. As far as I can see, there have been a number of attempts and proprietary schemes, but it LOOKS like none of them have any real traction.
Thanks for the response! |
Mark
tweetin' at mminasi |
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aed
Honorable But Hopeless Addict
USA
1213 Posts
Status: offline |
Posted - 08/13/2012 : 1:05:32 PM
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| I'm late to the party as usual....but doesn't MS Windows Server have a feature called iSNS? I've not personally use it as our SAN was only recently purchased and still small in terms of only a few servers connection to it but the iqn for zoning. |
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I don't *get* what IQNs do
