Hi I have been lurking for a short time and this is my first question for all you gurus :)
We have a XP1024 array (rebadged HDS 9980V I believe) connected via 4 2GB HBA's to a HPUX 11.23 PA-RISC running Veritas Storage Foundation 4.1 for Oracle. I am looking the recommended partitionsize to use when using the default 'iopolicy' of balanced. The default partitionsize is 1024 (kernel parameter dmp_pathswitch_blks_shift=10). I've heard the when the path switches frequently, the XP1024 has considerable overhead to manage internally to keep track of IO's in the cache etc... http://docs.hp.com/en/5187-1370/ch01s04.html - this document shows the optimal setting for a HDS 9960V is 14 to 16 (16384 to 65536). It has been speculated that the optimal value for the XP1024 is 17 (2^17 = 131072). Changing the kernel parameter parameter dmp_pathswitch_blks_shift requires a reboot, but I understand that this can be changed on-the-fly with 'vxdmpadm setattr enclosure XP10240 iopolicy=balanced partitionsize=131072' We are also considering the difference in iopolicy, such as 'adaptive' and whether or not adaptive will use the partitionsize parameter or is it only relevant to the 'balanced' iopolicy? Thanks Johnny
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