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2567
August 3rd, 2012 12:00
cx3-40: how to assign a lun only to a host and not to the storage group
Hi All,
I'm pretty new to SAN administration and I have a linux cluster with two servers that are assigned multiple LUNs right now through a storage group, of which they're both part of.
Those luns are used as OCFS2 luns in the cluster.
Now, I'm trying to assign "local" luns to both nodes with different lun_ids for local storage purposes. I don't want the LUNS to be seen by both nodes.
LUN 1 to server1 only.
LUN 2 to server2 only.
I can't seem to grasp how to do that through navisphere. If I try to assign a lun to server1, it says that it will assign it to the "storage group" that contains both of my servers.
It doesn't seem that I can assign a lun to the "host" only instead of the storage group that it is part of.
I must be missing something ??
Thanks,
Frank.
dynamox
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20.4K Posts
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August 3rd, 2012 12:00
i am afraid you can't do that. A host can only belong to one storage group, LUNs on the other hand can belong to multiple storage groups. So if you had this configuration, that would work:
storage group 1 = host 1 , LUN 0 , LUN 3
storage group 2 =host 2, LUN 1, LUN 3
lapfrank1234
23 Posts
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August 3rd, 2012 13:00
got it.. so it sounds like this was a design decision made by the admin, and if I needed to do what I explained, I would have to change the whole thing and create one storage group per cluster node and just assign the luns to both instead.
that makes complete sense and would unfortunately require some downtime.
thanks a lot!
Frank.
etaljic81
1K Posts
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August 3rd, 2012 13:00
Good point.
lapfrank1234
23 Posts
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August 3rd, 2012 13:00
thanks guys!
and yep, I thought that maybe using NPIV would work too, different WWNs, etc.. I'll certainly avoid doing that. I'll save those resources for other boxes.
dynamox
9 Legend
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20.4K Posts
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August 3rd, 2012 13:00
not necessarily. In cluster environment you may need to present LUNs that are not shared ..for example my Oracle RAC servers need to have file systems where they store binaries and those are added to local volume group on the host, not shared ASM disk groups.
dynamox
9 Legend
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20.4K Posts
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August 3rd, 2012 13:00
if you were using Cisco UCS where you can create virtual HBAs, or drop another set of HBAs in the host ..you could register them manually and treat them as "different" hosts and add them to other storage groups. More zoning, more resources (if physical HBAs) ..but doable.
etaljic81
1K Posts
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August 3rd, 2012 13:00
Are those Linux servers boot from SAN by any chance? That's the only reason why you would create two storage groups, if the two hosts are boot from SAN. Just FYI
etaljic81
1K Posts
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August 3rd, 2012 13:00
You are correct. Ignore my comment
lapfrank1234
23 Posts
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August 3rd, 2012 13:00
no they're not booting from SAN. They're both using internal storage for that.
from what I understood, if I want:
host 1 -> lun 0 used for /local_storage/node1
host 2 -> lun 1 used for /local_storage/node2
host 1-2 -> lun 3,4,5,6,... used for oracle ASM storage.
then, I also need to create two storage groups, even though I'm not booting on SAN. right ?
storage group1 would have lun 0 and 3,4,5,6
storage group2 would have lun 1 and 3,4,5,6