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9667
HLU 0/LUNZ
Do we always need to have HLU 0 in every storage grp. last week we had an issue. EMC recommenced us to have 1GB LUN with HLU 0 and this will remove the LUNZ.
This post is more than 5 years old
217 Posts
0
9667
Do we always need to have HLU 0 in every storage grp. last week we had an issue. EMC recommenced us to have 1GB LUN with HLU 0 and this will remove the LUNZ.
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kelleg
4.5K Posts
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March 25th, 2010 08:00
you can two solutions:
1. bind a very small LUN - 1MB - and assign it HLU 0 when you add it to the storage group but before you click apply - in the box when the HLU is locationed you can right-click to select the number
2. disable arraycommpath - this is really only used when you first connect a host to the array - it provides a target - PowerPath uses it to set up the first time - once all your LUNs are assigned, you can disable. Changing the arraycommpath requires a host reboot/reconfig
glen
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emc107962
The arraycommpath option enables or disables a communication path from the server to the storage system when LUN 0 is not configured on the storage system. Enabling arraycommpath from Navisphere instructs the array to present a LUNZ whenever a host LUN0 does not exist. If a host LUN0 is available to the server (LUN0 bound and no Access Logix or LUN0 in the Storage Group for the initiator), the status of arraycommpath does not matter. If arraycommpath is not set appropriately at initial host and array configuration, the host will not be able to see the storage system or the LUNs (in which case PowerPath and failover is irrelevant). In summary, arraycommpath does not play any role in failover. That is done by the failovermode setting.
Refer to solution emc99467 for information on the correct arraycommpath settings for all supported operating systems.
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emc76273 - How to change arraycommpath and failovermode settings using navicli
Note: Changing these parameters may cause the storage system to reboot.
Failovermode
Use the following Navisphere CLI command to configure failovermode:
navicli -h <SP_IP_address> storagegroup -sethost -host <hostname> -failovermode X
Where X=0, 1, or 2
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Message was edited by: kelleg
kelleg
4.5K Posts
1
March 24th, 2010 11:00
You don't actually have to if you're not using PowerPath. To disable you need to set "arrarycompath" to disabled - that will stop the array from sending the LUNZ to the host.
What OS are you using?
LUNZ is used to send to the host the first LUN before you have configured LUNs and Storage Groups.
glen
see Knowloedgebase article emc65060 for more information or doa search for the keyword "LUNZ"
Message was edited by: kelleg
RRR
5.7K Posts
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March 25th, 2010 03:00
In most production environments I see each host always starts at HLU0, so we don't have the "problem".
modaslam
217 Posts
0
March 25th, 2010 06:00
till now we are not bother about the HLU. so when you add first lun by default HLU 0 is assigned. but due to some reason we were asked to give them HLU 25. and then we had this LUNZ issue.
modaslam
217 Posts
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March 25th, 2010 06:00
kelleg,
we are using Solaris 10. powerpath is already installed(5.1). but our HLU was starting from 25.
Thanks for the primus number. we already had a management station to manage this array and we also have other host connected to it. then why did the Clariion pushed the LUNZ to the host. I need to check what was the arrarycompath set to.
modaslam
217 Posts
0
March 26th, 2010 07:00
the issue is resolved now.
So My understanding is if the arraycommonpath is enabled on host. you need to have a HLU 0 else we will end up in seeing LUNZ even if we have Powerpath installed.
thanks Kelleg!
AranH1
2.2K Posts
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March 26th, 2010 08:00
I am curious. What kind of issues occurred with the LUNZ being presented to your host?
AranH1
2.2K Posts
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March 26th, 2010 09:00
I have never had issues with this. Are the errors just logged or does it potentialy affect the host negatively?
kelleg
4.5K Posts
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March 26th, 2010 09:00
You see a disk that you can't format or access and it spits out errors
glen
kelleg
4.5K Posts
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March 26th, 2010 10:00
Talking about UNIX - just logged - never saw any issues other than logs filling with errors - the messages cause more problems than the LUNZ does.
glen