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2387
October 21st, 2015 04:00
Sp-A and Sp-B seperate connection
Hello Team,
It is very urgent need , requiements
i have one EMC with attached to 1+1 cluster blades with A0 , A1 , B0 and B1 FC cables(no switch). I need to add two more new blades 1+1 in same chassis , but will use same EMC (no FC switch). I removed A0 and B1 from old blades and attach them to new blades , after this activity my veritas cluster was not coming up and veritas was no able to recognize the disk groups.
LUN's were shuffling between SP-A and SP-B inside navisphere GUI.
After all this , i re-attach the cables and use some commands from here and there to again recongize my Disk Groups. It was done.
Now , i need to use same EMC for new blades , so now i am thinking to move all the LUN in SP-B to SP-A and give them current owner and default Owner, so no LUN left in SP-B . Now i will remove B0 and B1 cable from old blades and attach them to new one, create new LUN and make there owner as SP-B. Will this thing will work perfectly.
There will be no redundancy but this is fine as old blades need to be removed after sometime but while installing i require new blades connected with EMC with new LUN.
Please help me on this and provide your valuable suggestions soon.
kelleg
4.5K Posts
0
October 22nd, 2015 08:00
See comments below:
2. I need to assign all LUN to SP-A as there current and default owner ( No LUN in SP-B).
This is fine - the host failover policy that is currently connected to the array will need to be changed (what the host will use as the default path to the LUNs once those LUNs are moved to SPA). This will end with the two blade servers with only a single path for each server to SPA. This is not recommended as you leave yourself open if SPA fails.
3. I need to disconnect cable of SP-B from server blades 0 and 1 , i want them to run with single SP-A.
Again, this OK but not recommended as a you now have a single point of failure for the two hosts.
4. I am connecting new Server blades 2 and 3 , want to use same EMC , so i will create new LUN and new storage group inside same EMC and will connect SP-B cables to those blades. Make current owner and default owner to of new LUN to SP-B and assign them new storage group.
Again this is doable and will work but again you leave yourself open if you have a failure. I would recommend that adding a switch would help configure the array for more redundancy.
glen
kelleg
4.5K Posts
0
October 21st, 2015 09:00
1. it is always helpful to state the model of EMC array - ie. VNX 5300 - what model EMC array are you using?
2. If the LUNs on the array are in Pools (Virtual Provisioning) then you can NOT change the Default SP owner - it must always match the Allocated SP owner. If the LUNs are in raid groups then you can change the Default SP owner and trespass the LUN. You should be careful that you do not unbalance the workload for SPA and SPB - not too many LUNs on SPA vs SPB
Not sure what you mean by removing blades - are you referring to the server blades? If you are trying to replace an old server with a new server and use the same LUNs on the EMC array, they you will need to do more than just swap out the server - your LUNs would be expecting that the server connected to the SP ports is the one that you removed. You will need to go through the installation setup for adding a new server, then at some point add that server to the Storage Group that holds the LUNs. ON the array you will need to remove the old server from the exisiting Storage Group and add the new server in - this will require that you register the new server first. You may need to contact your local EMC account team for assistance.
glen
akmani1987
3 Posts
0
October 21st, 2015 18:00
hello Glen,
Thanks for reply.
1. EMC is AX-4 series.
2. I need to assign all LUN to SP-A as there current and default owner ( No LUN in SP-B).
3. I need to disconnect cable of SP-B from server blades 0 and 1 , i want them to run with single SP-A.
4. I am connecting new Server blades 2 and 3 , want to use same EMC , so i will create new LUN and new storage group inside same EMC and will connect SP-B cables to those blades. Make current owner and default owner to of new LUN to SP-B and assign them new storage group.
So , configuration will be like Sp-A(A0 and A1 cables ) for Blade 0 and 1 , and SP-B(B0 and B1 cables) for Blade 2 and 3.
Will this above configuration work perfectly ?
akmani1987
3 Posts
0
October 22nd, 2015 21:00
thanks a lot Glen,
best option is to have Switch , but we don't have it and don't want to also , so looking for other work arounds.
Your reply helped me a lot.
Just one thing i need to know. I will stop my cluster , make server blades down and then tresspass lun from b to A(will this only steps to be followed or are there any other you want to suggest.)
After lun move to SP-A , i will execute powermt reconfigure and navishpere update...
kelleg
4.5K Posts
0
October 23rd, 2015 07:00
If you're using PowerPath, you should not need to power down the servers. Just pull the B-Side cables and the LUNs should trespass to SPA. Then run the powermt config, then reconfig or save - you may need to reboot the servers, but sure about that part.
If I remember correctly, AX4 came with a PowerPath Basic license so that only supports one HBA per server and two paths anyway.
glen