• Add a Comment
  • Edit
  • More Actions v
  • Quarantine this Entry

Comments (5)

1 AnthonyEnglish commented Permalink

Good one, Chris. I never thought of using priority 255. I've only ever used 1 and 2!

2 PontiacGeronimo commented Permalink

Is there any script (IBM's) for paths prioritization in configuration like: <div>&nbsp;</div> NPIV, dual-vios, two HBAs on each VIOS <br /> 4 virtual FC adapters on LPAR <br /> 6 diskd/LUNs on LPAR <br /> 192 paths in total (32 paths per LUN = 8 paths via each of 4 adapters for each LUN) <div>&nbsp;</div> LUN1,2,3 - from storage box#1 <br /> LUN4,5,6 - from storage box#2 <div>&nbsp;</div> Now I have if configured so: <div>&nbsp;</div> LUN1 priority 1 for fscsi0 -&gt; via VIOS1 HBA1 <br /> LUN1 priority 2 for all fscsi1,2,3 (the rest) <div>&nbsp;</div> LUN2 priority 1 for fscsi1 -&gt; via VIOS1 HBA2 <br /> LUN2 priority 2 for all fscsi0,2,3 (the rest) <div>&nbsp;</div> LUN4 priority 1 for fscsi2 -&gt; via VIOS2 HBA1 <br /> LUN4 priority 2 for all fscsi0,1,3 (the rest) <div>&nbsp;</div> LUN5 priority 1 for fscsi3 -&gt; via VIOS2 HBA2 <br /> LUN5 priority 2 for all fscsi0,1,2 (the rest) <div>&nbsp;</div> LUN3 priority 1 for fscsi0 -&gt; via VIOS1 HBA1 <br /> LUN3 priority 2 for all fscsi1,2,3 (the rest) <div>&nbsp;</div> LUN6 priority 1 for fscsi3 -&gt; via VIOS2 HBA2 <br /> LUN6 priority 2 for all fscsi0,1,2 (the rest) <div>&nbsp;</div> So, when fscsi3 fails, LUN6,5,1 will go via fscsi0 <div>&nbsp;</div> and when VIOS2 will fail, LUN1,3,4,5,6 will go via VIOS1 fcs0 and only LUN2 via VIOS1 fcs1... <div>&nbsp;</div> any suggest how to get optimal and reliable configuration?

3 cggibbo commented Permalink

Hi PontiacGeronimo, <div>&nbsp;</div> hdisk path priorities only apply to VSCSI environments. <div>&nbsp;</div> When using NPIV and virtual FC adapters, it is best to use MPIO. VSCSI only allows for failover only not real MPIO. True MPIO will allow you to use an appropriate MPIO algorithm such as round_robin. This will depend on your storage type and MPIO device drivers. <div>&nbsp;</div> You may want to take a look at my article on NPIV: <div>&nbsp;</div> http://www.ibm.com/developerworks/aix/library/au-NPIV/index.html <div>&nbsp;</div> Or this document: <div>&nbsp;</div> http://www-03.ibm.com/support/techdocs/atsmastr.nsf/5cb5ed706d254a8186256c71006d2e0a/383b52f8b7b82eda862577b300566c6a/$FILE/Power%20Systems%20SAN%20Multipath%20Configuration%20Using%20NPIV%20v1.2.pdf <div>&nbsp;</div> Cheers. <div>&nbsp;</div> Chris

4 cggibbo commented Permalink

This document is also very helpful: <div>&nbsp;</div> Disk path design for AIX including SAN zoning: <div>&nbsp;</div> http://www-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/WP101914 <div>&nbsp;</div> Cheers. <div>&nbsp;</div> Chris

5 AhmedAmer commented Permalink

Excellent article ,Chris! <div>&nbsp;</div> Recently , I wrote a couple of articles about "storage paths" management : <br /> http://unixhood.com/main/2013/02/26/change-the-status-of-a-path-to-storage/ <br /> http://unixhood.com/main/2013/02/26/how-to-remove-a-path-to-your-san-storage/

Add a Comment Add a Comment