hi Guys,

Since we upgraded our db2 instance to 64 bits and enable CIO/DIO in all the Database filesystems noticed that we are having some performance degradation. Even more the Database backups that use to take only 2 hours is now taking between 5 and 6 hours. In our environment we are running AIX 5.4 and db2 fixpack 12 64 bits. Also this database is only 150 gigs. Thanks for any help.

cheers,

harby

Are you writing the backup images to the file systems that have direct I/O enabled?

Also, do you actually have the hardware for CIO? There is not a really compelling point to do concurrent I/O if you have just a single disk, I would say.

concurrent I/O takes data directly from disk to buffer pool(not disk to filecache and the from filecache to bufferpool); gives you the functionality of raw file space with the convenience of cooked file systems; if you use tivoli, make sure the api64 dsm.sys has same parameters as the api(32) dsm. sys; util_heap-size is where backup is formatted; make sure it is increased; you can reduce the filecache minperm%=2 maxperm%= 30 and increase all db buffer pools and heap sizes