The last five lines of the vmstat -v report are useful when you're looking for I/O problems. The first line is for disk I/Os that were blocked because there were no pbufs. Pbufs are pinned memory buffers used to hold I/O requests at the logical volume manager layer. Prior to AIX v5.3, this was a systemwide parameter. It's now tuneable on a volume-group basis using the lvmo command. The ioo parameter that controls the default number of pbufs to add when a disk is added to a volume group is pv_min_pbuf, and it defaults to 512. This specifies the minimum number of pbufs per PV that the LVM uses, and it's a global value that applies to all VGs on the system. If you see the pbuf blocked I/Os field above increasing over time, you may want to use the lvmo -a command to find out which volume groups are having problems with pbufs and then slowly increase pbufs for that volume group using the lvmo command. I normally increase the global value to 1,024.
Paging space I/Os blocked with no psbuf refers to the number of paging space I/O requests blocked because no psbuf was available. These are pinned memory buffers used to hold I/O requests at the virtual memory manager layer. If you see these increasing, then you need to either find out why the system is paging or increase the size of the page datasets.
Filesystem I/Os blocked with no fsbufs refers to the number of filesystem I/O requests blocked because no fsbuf was available. Fsbufs are pinned memory buffers used to hold I/O requests in the filesystem layer. If this is constantly increasing, then it may be necessary to use ioo to increase numfsbufs so that more bufstructs are available. The default numfsbufs value is determined by the system and seems to normally default to 196. I regularly increase this to either 1,024 or 2,048.
and i lost what i typed previously