Disk Enclosures
Showing results for 
Search instead for 
Did you mean: 

EVA Load Balancing question

Go to solution
Ian Dennison_1
Honored Contributor

EVA Load Balancing question

I have an EVA-5000 with firmware 3.028 and SecurePath connected to HP-UX 11.11 Servers.

I have been looking for ways to improve performance and was wondering, does the following output show usage of both EVA controllers as part of "least IO" rule, or is controller P5849E1AAPY077 not used at all for this disk? Would allocating disks across EVA controllers show a possible performance increase?

Share and Enjoy! Ian

Server: bc999999.domain.net Report Created: Wed, Apr 11 09:51:35 2007
Command: spmgr display
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Storage: 5000-1FE1-5002-8B02
Load Balance: On Auto-restore: On Balance Policy: Least I/O
Path Verify: On Verify Interval: 30
HBAs: td0 td1
Controller: P5849E1AAPY055, Operational
P5849E1AAPY077, Operational
Devices: c20t0d0 c20t0d1 c20t0d2 c20t0d3 c20t0d4 c20t0d5 c20t0d6

TGT/LUN Device WWLUN_ID H/W_Path #_Paths
0/ 0 c20t0d0 6005-8B02-0001-3AA7-0002-0000-0050-0000 4
Controller Path_Instance HBA Preferred? Path_Status
P5849E1AAPY055 no
c3t0d1 td0 YES Active
c14t0d1 td1 YES Active

Controller Path_Instance HBA Preferred? Path_Status
P5849E1AAPY077 no
c5t0d1 td0 no Standby
c12t0d1 td1 no Standby

Building a dumber user
Uwe Zessin
Honored Contributor

Re: EVA Load Balancing question

Controller P5849E1AAPY077 is not used for I/Os to the virtual disk with the LUN WWN 6005-8B02-0001-3AA7-0002-0000-0050-0000.

However, the server does access this virtual disk via Fibre Channel adapters |td0| and |td1|, because you have turned on load-balancing and you see two 'Active' Paths:
c3t0d1 td0 YES Active
c14t0d1 td1 YES Active

To check if Controller P5849E1AAPY077 is owning any virtual disks - after all, Secure Path lists 6 more devices: c20t0d1 c20t0d2 c20t0d3 c20t0d4 c20t0d5 c20t0d6 - you need to go over the full list from SPMGR and check if any Active paths to that controller are visible.

If not, I would equally divide the virtual disks across both controllers. You win a second CPU for I/O processing and the second controller's cache memory (512MByte read, 256MByte write).