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2 Intern
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220 Posts
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994
August 25th, 2010 12:00
Lun Offset in symmetrix
Hi
What is lun offset in symmetrix ?
how to list the lunoffset ?
How it will affect the lun number seen by the host for the corresponding sym device? Because lun number looks differnt from the symmetrix to the host if the lun is offset
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Amita2
93 Posts
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August 26th, 2010 08:00
Hi
Lunoffset Sets the record in the database to hold base and offset information about a skip hole in the host-visible sequence of LUN addresses.
The base value is essentially the host’s first missing LUN in the skiphole.
The offset is the hole size (number of addresses needed to skip over the hole).
When the host asks for a LUN that is equal to, or greater than the skip hole base value, the offset is added to the LUN value requested by the host to render the actual LUN (device) in the EMC Solutions Enabler Symmetrix 174 Array Controls Version 7.0 CLI Product Guide Device Masking Symmetrix array.
For Example: for host A you mask devices 0000-0003 and 0007-0009 to Host B.
Here Host B needs to see LUN 000 first, you would have to set lunoffset ON with a base value of 000 and an offset of 7.
To set Lunoffset use : symmask -sid SymmID set lunoffset on offset base -awwn awwn -dir # -p #
To see the LUN ID seen by Host : symdev -sid SymmID show dev ( Under Lun Symm and LUN HOST coulumn you can see the Lun addressed in Symm and LUN addressed to Host.)
Regards
Amita
ZepHead
88 Posts
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August 25th, 2010 13:00
Please download the Solutions Enabler download kit from PowerLink, that will contain information about this and much more..
You can also search for this subject in knowledgebase... Found a few that might help: emc97267, emc194174, emc95866 and emc101422, as an example.. But encourage to look around some more.
Here is a snippet from the "SE Array control guide" - as an example:
A new command,
symaccess, provides all the storage provisioning requirements for
Symmetrix V-Max arrays running Enginuity 5874.
With
symaccess, the following device masking functions are no longer supported:
◆
There is no device masking database. With the symaccess command, all groups
and views are backed up to a file, and can be restored from a backup file.
◆
Volume visibility and the LUN offset on an initiator are no longer supported.
◆
Heterogeneous host types are no longer supported. The HBA flags option is
supported.
Again, these documents are extremely informative.. Take a look..
rawstorage
4 Apprentice
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423 Posts
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August 26th, 2010 01:00
If you are using enginuity 5772 you have dynamic lun addressing available to you; This is a much more flexible method see emc194174