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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI: 2.2.6. Naming & mappingSorry folks, I read Jim Hafner's note, after I sent the note. Jim states: {Snip} The EVPD page 83h LU WWIdentifier (or whatever it's called) spec'd in SPC-2 has just be made mandatory for SPC-2 (at yesterday's T10 meeting). So iSCSI needn't ask this as a requirement. {Snip} So please do not answer the question I asked in the attached note. Now lets get back to the iSCSI spec. . . . John L. Hufferd John Hufferd/San Jose/IBM@IBMUS@ece.cmu.edu on 09/16/2000 09:20:02 PM Sent by: owner-ips@ece.cmu.edu To: Charles Monia <cmonia@NishanSystems.com> cc: ips@ece.cmu.edu Subject: RE: iSCSI: 2.2.6. Naming & mapping Charles, Though I think you are being very kind in your interpretation of Pierre's note, you may have a point. Though I do not know why it is optional when you have multiple connections -- the Spec does, however, say that the VPD is optionally returned by the Inquire Command. I think it is universally applied when a Storage Controller has multiple connections, however, your point may be -- that should we just state it as a non optional feature of storage controllers that support iSCSI. I can not see why this would be a problem. Does anyone else? . . . John L. Hufferd Charles Monia <cmonia@NishanSystems.com> on 09/16/2000 03:31:57 PM To: Pierre Labat <pierre_labat@hp.com>, John Hufferd/San Jose/IBM@IBMUS, ips@ece.cmu.edu cc: Subject: RE: iSCSI: 2.2.6. Naming & mapping Apologies for the clutter if someone else has already responded to this. > -----Original Message----- > From: Pierre Labat [mailto:pierre_labat@hp.com] > Sent: Thursday, September 14, 2000 5:57 PM > To: John Hufferd/San Jose/IBM; ips@ece.cmu.edu > Subject: Re: iSCSI: 2.2.6. Naming & mapping > > > John Hufferd/San Jose/IBM wrote: > > > Folks, > > We are again mixing issues and layers again. > > > > There is NO SUCH THING as an iSCSI LU. There is an iSCSI > device which is a > > Controller which will have a SCSI layer which in turn > supports an LU. Once > > the iSCSI session is established, the Rules of SCSI define > how the LUs are > > addressed. > > I agree. > > > There maybe additional Database (LDAP) processes and > > information that attempts to relate LU #3 known to Host xyz > to some name > > "abcd...." etc. > > I don't want so much, i would want just to have a unique > identifier per LU. > It doesn't cost a lot and it will have the advantages > described in the first > mail below. > Hi: As I read Pierre's note, he is proposing that support for the heretofore optional Device Identification page be added to the list of features that must be supported by an iSCSI device. I believe that's the issue the ips wg ought to be debating. (See ftp://ftp.t10.org/t10/drafts/spc/spc-r11a.pdf, section 8.4.3, for a description). Charles > > But that is NOT an iSCSI Transport Protocol. We may need > > to work on this at some point but it is not an iSCSI > transport issue. > > > > Yes, it is not a transport issue, but why not request that > now before people > start > building iSCSI controllers if it simplifies the life of everybody? > I don't know how FC managed to have their WWN but why could not we > do the same thing? > > Regards, > > Pierre > > > > > . > > . > > . > > John L. Hufferd > > > > Pierre Labat <pierre_labat@hp.com>@ece.cmu.edu on > 09/14/2000 10:06:54 AM > > > > Sent by: owner-ips@ece.cmu.edu > > > > To: ips@ece.cmu.edu > > cc: > > Subject: Re: iSCSI: 2.2.6. Naming & mapping > > > > julian_satran@il.ibm.com wrote: > > > > > Not again (what is the sign for frustration?)... I mean > not before the > > next > > > version. > > > > > > Julo > > > > > > Raghavendra Rao <Jp.Raghavendra@EBay.Sun.COM> on > 14/09/2000 21:04:02 > > > > > > Please respond to Raghavendra Rao <Jp.Raghavendra@EBay.Sun.COM> > > > > > > To: Julian Satran/Haifa/IBM@IBMIL > > > cc: > > > Subject: iSCSI: 2.2.6. Naming & mapping > > > > > > I feel that a LUN should be very much part of the Naming scheme > > > that has been proposed in the draft, regardless of the level of > > > enforcement of the scheme by implementors. LUNs are very much > > > part of SCSI addressing, and where LUN doesn't exist, zero is > > > assumed. > > > > > > Without a LUN identifier, Naming section doesn't look complete. > > > > > > Do you have insights why it is omitted ? Is this by > design or overlook ? > > > > > > Thanks. > > > -JP > > > > About the topic of naming a LU, what seems to be a benefit > for me, is to > > adopt the same requirement as fibre channel: each LU MUST provide a > > unique identifier (from the Device Identification Page). > > >From what i read it seems that it is not a big deal to add > this page in a > > LU. > > However, this unique identifier is not needed for iSCSI > protocol to work. > > It doesn't interact with the protocol. > > > > But from an administration point of view, to configure a > server using > > storage > > through iSCSI, the existence of this unique identifier helps a lot. > > It allows the configuration product to know/check if various LUNs > > correspond > > to the same LU, it could help to manage the LU migration > (the LUN is > > changed > > > > inside a target for the same LU). > > It simplifies the configuration software by avoiding it to > fake a unique LU > > identifier. > > It will help in having a configuration tool for iSCSI that > can be closer to > > the one > > used with FC. > > > > Is somebody knowing if it is planned to incorporate this Device > > Identification > > Page > > in the iSCSI LU? Will it be mandatory? Which format > (identifier type) will > > be > > used? > > FC uses the type 3 (FC_PH Name_Identifier). > > > > Regards, > > > > Pierre >
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