Jaqui's AIX Performance and Security Blog
04 09 2008

Thu, 04 Sep 2008


Latest Tunable recommendations for AIX v6 and AIX v5.3 BOTH NETWORK no -p -o rfc1323=1 no -p -o sb_max=1310720 no -p -o tcp_sendspace=262144 no -p -o tcp_recvspace=262144 no -p -o udp_sendspace=65536 no -p -o udp_recvspace=655360 Also check the actual NIC interfaces and make sure they are set to at least these values For AIX v5.3 No need to set memory_affinity=0 after 5.3 tl05 MEMORY vmo -p -o minperm%=3 vmo -p -o maxperm%=90 vmo -p -o maxclient%=90 vmo -p -o minfree=960 vmo -p -o maxfree=1088 vmo -p -o lru_file_repage=0 vmo -p -o lru_poll_interval=10 The parameters below should be reviewed and changed (see vmstat v and lvmo a later) PBUFS ioo -p -o pv_min_pbuf=1024 JFS2 ioo -p -o j2_maxPageReadAhead=128 j2_dynamicBufferPreallocation=16 Default that may need tuning Replaces tuning j2_nBufferPerPagerDevice JFS ioo -p -o numfsbufs=1024 ioo -p -o maxpgahead=16 For AIX v6 Make the network changes above Memory defaults are already correctly set and should not be changed If you upgrade from a previous version of AIX using migration then you need to check the settings though The parameters below should be reviewed and changed (see vmstat v and lvmo a later) PBUFS Tune these using lvmo for the individual volume group pv_min_pbuf is now a restricted tunable JFS2 ioo -p -o j2_maxPageReadAhead=128 (default above may need to be changed for sequential) j2_dynamicBufferPreallocation=16 Default that may need tuning Replaces tuning j2_nBufferPerPagerDevice JFS ioo -p -o numfsbufs=1024 (now restricted) ioo -p -o maxpgahead=16 (now restricted) CHANGES TO CONSIDER TO ADAPTERS AND HDISKS Check to make sure your vendor supports these: fcs0 etc adapters init_link pt2pt INIT Link flags True max_xfer_size 0x200000 Maximum Transfer Size True num_cmd_elems 2048 Maximum number of COMMANDS to queue to the adapter True Be careful with init_link as it defaults to AL - this setting is switch and SVC dependent. Check queue_depth for hdisks - lsattr -El hdisk? Use iostat -aD to look for sqfull conditions that would indicate the need for an increase in queue_depth


posted at: 22:57 | path: | permanent link to this entry