Jaqui's AIX Performance and Security Blog
03 12 2007

Mon, 03 Dec 2007

Latest Set of General Purpose AIX v5.3 Tunables Please ensure you test these first before implementing in production as your mileage may vary 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 nfso -p -o rfc_1323=1 nfso -p -o nfs_socketsize=600000 nfso -p -o nfs_tcp_socketsize=600000 Memory Settings vmo -p -o minperm%=5 vmo -p -o maxperm%=90 vmo -p -o maxclient%=90 vmo -p -o minfree=1000 vmo -p -o maxfree=1200 vmo -p -o lru_file_repage=0 vmo -p -o lru_poll_interval=10 Leave strict_maxperm and strict_maxclient at their defaults IO Settings Leave minpgahead and J2_minPageReadAhead at their defaults of 2 ioo -p -o j2_maxPageReadAhead=128 ioo -p -o maxpgahead=16 ioo -p -o j2_nBufferPerPagerDevice=1024 ioo -p -o hd_pbuf_cnt=1024 ioo -p -o numfsbufs=2048 ioo -p -o pv_min_pbuf=1024 #### this is the 5.3 value - below is the one for 5.2 ### ioo -p -o pv_min_pbuf=1024 If doing lots of raw I/O you may want to change lvm_bufcnt Default is 9 ioo -p -o lvm_bufcnt=12 Others left to default that you may want to tweak include: ioo -p -o numclust=1 ioo -p -o j2_nRandomCluster=0 ioo -p -o j2_nPagesPerWriteBehindCluster=32 ioo -p -o j2_maxRandomWrite=32 ioo -p -o maxrandwrt=32 These are starting points only Other areas to look at tuning: Fiber cards Check out max_xfer_size - 0x100000 is 16mb dma, 0x200000 is 128mb dma For heavy I/O you may want to change this to 128mb hdisks Check out queue_depth. If seeing sqfull on iostat -D then increase queue_depth if your disk subsystem allows it

posted at: 09:48 | path: | permanent link to this entry