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MA6000 HP-UX LUN-id > 7 not seen

Kurt Beyers.
Honored Contributor

MA6000 HP-UX LUN-id > 7 not seen

Hi,

I've got a MA6000 connected to a HP-UX server (HPUX 11.0). Two new LUN's were defined on the MA6000 array, but a LUN with a LUN-id > 7 was not seen by the HPUX server (ioscan and insf-e discovered only one of the 2 new LUN's that had a LUN-id < 7).

After changing the LUN-id of the other LUN to an id below 7, it was discovered as well by an ioscan.

Are there some patches required or a kernel parameter that must be increased to detect LUN's larger than 7?

regards,
Kurt
18 REPLIES
Michael Tully
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Hi Kurt,

HPUX uses a what they call a VBUS (virtual BUS). There is no LUN number defined above 7. They only have a range of 0-7. There is a document I've seen in the forums on this and I have it bookmarked, but I'm not in the office now. If someone doesn't list, I have a look tomorrow morning my time.

There is no patch nor kernel parameter. I know using an EMC array you have to define the VBUS number. Perhaps it is the same with this piece of equipment.

HTH
Regards
Michael
Anyone for a Mutiny ?
Vladimir Vybiral
Valued Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Hello, HP-UX is a SCSI2 protocol running operating system, so all scsi2 limitations apply - 16 targets per bus, 8 luns per target (0-7) so if there is no patch I would not know about, a lun with a higher number than 7 will not be seen by the OS. On fibre channel systems, there are several ways of going around this - either LUN offsetting as done on HSG controllers, or virtual bus/virtual target/virtual lun as done with VA arrays (this will translate fe. LUN7 and LUN9 into bus0,target0,lun7 and bus0,target1,lun1). BR, Vladimir
When speaking, Your words should sound better than Your silence - Arabic proverb
Eugeny Brychkov
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

If this MA is FC connected then your issue means it uses Target addressing mode, but not volume set as it should as a disk array.
Please attach 'ioscan -fn' and how MA is connected to the host to your next reply
Eugeny
Kurt Beyers.
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

The MA6000 is fibre attached (with a Compaq switch in between the HP server and the MA6000). There are 2 fibre HBA in the HPUX server and two Compaq switches. The Secure Path software (version 3.0A service pack 1 for HPUX) presents the 4 physical paths to the LUN's as a single logical path

I know that a LUN > 7 on the MA6000 will be translated in a hardware path ctd where z will always be smaller or equal to 7 and that you can calculate out of x, y and z the actual LUN number. My point is that the LUN was not seen when the LUN-id was larger than 7 and was discovered when the LUN-id was changed to a value below 7, nothing on the HP-UX server changed.

Attached is the output of an 'ioscan -fnk' and 'ioscan -fnkC disk'. The Secure Path was still version 3.0 when the ioscan was taken. After the upgrade to Secure Path version 3.0A SP the device files to the disks changed to c14t0d instead of c12t0d. The two new LUN's are not yet in this ioscan but received finally the device files c14t0d0 and c14t0d7.

regards,

Kurt
Eugeny Brychkov
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

I'm right. Target addressing mode. In this mode no more than 8 LUNs. Please attach supportshow output from brocade zipped. I will return here as soon as will have any useful info
Eugeny
Kurt Beyers.
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Eugeny,

it is a Compaq switch and not a Brocade switch. I'm not managing the switch and a collegue of my didn't know what you mentioned with the showsupport command.

But he said that the problem has to be on the HPUX server, as the LUN was seen after changing the LUN-id on the MA6000.

Can you be pore specific about the information you want?

regards,

Kurt
Eugeny Brychkov
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

I rephrase: is this CPQ switch OEMed from brocade?
I see that MA works in public loop. Is it correct? Why do not you set it up to work in fabric (using MA CLI 'set this
port_1_t = fabric' and 'set this
port_2_t = fabric') and configure it to use SCSI-3 protocol instead of SCSI-2?
Make sure you have latest ACS installed
Eugeny
Vladimir Vybiral
Valued Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Hello Kurt, Eugeny,
Changing to fabric would not solve the situation, it is not tied to the problem Kurt is trying to solve, I think. The question is how to tell HP-UX to use volume set addressing. I am not a HP-UX expert, but You should definitely use SCSI2 mode and CCL (command console lun) presented. Command console lun should be visible to the host as LUN0, so if You create lun0 as a volume, You basically mask it. CCL is used besides other things also for querying LUNs higher than 7. So, I would recommend to check the array is in SCSI2 mode and CCL presented.
Next to Your LUNs 2-6, You should see also 1.16.255.x.y.0 where xy is AL_PA of Your hsg60 ctrl translated and 1.16.zz.0.0.0 CCL device... Once You see this, You have succeeded in switching the VBUS mode on... hmmmm, Vladimir
When speaking, Your words should sound better than Your silence - Arabic proverb
Eugeny Brychkov
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Vladimir,
you really know what're you talking about :o)
Kurt,
I've checked with our hpux expert and she said that it's storage device responsibility to tell hpux driver if it's fcparray or fcpdev.
So the items to check are:
1. check for HSG60 to give correct fcparray-capable responce to hpux driver. It usually done by assigning correct OS behavior to host (WWN assigned to 'hpux'). I know HSG80 is capable of it;
2. hpux should have LUN 0, at least virtual one, to query. So please create LUN 0.
Good luck!
Eugeny
Vladimir Vybiral
Valued Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Hello again,
Eugeny, I did not get whether You mean "You know what're You talking about" or "You are completely off" >:-| please explain or I will feel
However, I think that if You set CCL presentation in SCSI2 mode, the LUN0 is a virtual presentation done by the controller. If You create physical LUN0 and present it to the host, You mask the CCL device LUN and query will not get consistent results. In SCSI3 mode, the CCL device would migrate to other LUN number, basically the next one not used / which also would prevent HPUX from querying, as HPUX is able to query only LUN0 as CCL... BR and nice day, Vladimir
When speaking, Your words should sound better than Your silence - Arabic proverb
Eugeny Brychkov
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Vladimir, please excuse me if I said something incorrectly. I mean that YOU are absolutely RIGHT (positive meaning :oP )
Agree, definitely it should be SCSI2. But creating LUN 0 is good idea. Look at the ioscan Kurt attached. There's no LUN 0, even virtual!
Eugeny
Vladimir Vybiral
Valued Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Okay, the problem can be also me not being native speaker, so not getting the slight differences in english language :)
The LUN0 is not visible because I guess the HSG ctrl is in SCSI2, NO_CCL mode. I believe this is default on the device. So switching the CCL on with a command SET THIS COMMAND_CONSOLE_LUN should solve the query lun visibility. If You create LUN0 as a physical device with ADD UNIT D0 ..., it is not CCL and the query will in most cases not work as the lun is not giving the ux an information it is the fcparray device as You have said previously. BR, Vladimir
When speaking, Your words should sound better than Your silence - Arabic proverb
Vladimir Vybiral
Valued Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

hmm, sorry to keep this thread longer and longer. Forgot to say that the ccl should be set the same on both ctrls, so after set this command_console_lun You need to put set other command_console_lun, plus, after a change of ccl presentation the ctrls need to be restarted with restart other, restart this commands. That should be all. then ioscan -fnCdisk on the hpux and please attach the results. BR, Vladimir
When speaking, Your words should sound better than Your silence - Arabic proverb
Kurt Beyers.
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Attached is the latest ioscan -fnC disk. There is now a LUN 0 (LUN 1 is the other new LUN). This is one of the 2 new LUN's that has production databases on it. I still have troubles to follow the reasoning of Eugeny and Vladimir.

Kurt
Vladimir Vybiral
Valued Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

okay, is the LUN0 a physically created lun or is it the CCL device? have You run the set this command_console_lun command? If Yes, You should be able to see luns above 7 by now...
so in full ioscan, you should be seeing fc devices with 1.16.255.0.0.0 and 1.16.255.xx.yy.0 (where xx and yy if a translated AL_PA), both of them for lun0 and zz.0.0.0 with zz being Your AL_PA of the controller, also for lun0. If You see these, the device does so called volume set addressing which allows for the querying luns above 7. If You create lun 8 and do ioscan -fnCdisk, You should see a new disk device with 1.16.zz.0.1.0 If not, I start to feel there is something between Heaven and Earth...
When speaking, Your words should sound better than Your silence - Arabic proverb
Kurt Beyers.
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

The LUN 0 is a physically created LUN that contains production databases.

I'll check with the responsible of the MA6000 if the command_console_lun has been set on the controllers of the MA6000 and update the thread when I know more.

Thanks for your assistance so far,
Kurt
Vladimir Vybiral
Valued Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Hello again,

as You are using LUN0 for existing data (production database), the command_console_lun is probably disabled, if the array is in SCSI2 mode. Be aware that You would need to move the existing LUN to a different lun number before You enable the command console lun, otherwise You are about to lose access to Your data! in scsi2, CCL can be only LUN0 and will mask whatever lun exists as lun0. In SCSI3, CCL would migrate to next available lun number, but for HPUX, You cannot use other than 0 again... So, correct steps>
1. stop production DB
2. change LUN number for volume unit on lun 0 (present it as a different lun number
3. enable ccl
4. restart controller
5. mount production db lun and restart app
6. ioscan -fn
7. You should see the CCL as mentioned above
8. create lun8
9. ioscan
10. You should see the 16.0.1.1 disk device...

hmmmm, BR, Vladimir
When speaking, Your words should sound better than Your silence - Arabic proverb
Kurt Beyers.
Honored Contributor

Re: MA6000 HP-UX LUN-id > 7 not seen

Vladimir,

thanks for the good advise. I still have to discuss it with the collegue who configured the MA6000 and we will make sure to change the LUN number of the currently LUN 0 to another LUN number prior to enabling the CCL. Stop the database, vgexport the volume group, change the LUN number and vgimport it again. I've learned again some new things at the forums.

Kurt