Dan, We have done a lot of work on tuning AIX for UniVerse.
I looked into CIO and its potential benefits to UV. I even raised a case with U2 support. Their response was that as CIO essentially eliminates caching updates in memory it requires the update to be physically made to disk before the process can continue. The nature of UV (and possibly UD) updates made U2 support think there would not be much benefit. The biggest improvements we made were to how AIX manages memory and its I/O buffers. The memory changes made a huge different to process paging, and the I/O buffers played a large part in stabilising our I/O activities. These settings are the culmination of taking advised adjustments from various sources and then fine tuning for our UV installations. ___Memory Management____ Parameter Default New Value Command to Adjustment minperm% 20 5 vmo -p -o minperm%=5 maxperm% 80 90 vmo -p -o maxperm%=90 maxclient% 80 90 vmo -p -o maxclient%=90 lru_file_repage 1 0 vmo -p -o lru_file_repage=0 page_steal_method 0 1 vmo -p -o page_steal_method=1 ___PBUFS___ pv_min_pbuf 512 4096 ioo -p -o pv_min_pbuf=4096 ___JFS2___ j2_dynamicBufferPreallocation 16 128 ioo -p -o j2_dynamicBufferPreallocation=128 j2_nBufferPerPagerDevice 512 8192 ioo -p -o j2_nBufferPerPagerDevice=8192 ___JFS___ numfsbufs 196 2048 ioo -p -o numfsbufs=2048 maxpgahead 8 16 ioo -p -o maxpgahead=16 I found the following links very helpful when exploring the AIX performance tuning options: http://www.circle4.com/blosxomjl.cgi/ http://users.ca.astound.net/baspence/AIXtip/j2_buffer.htm This PDF explains the benefits of tuning Memory: http://www.ibm.com/developerworks/wikis/download/attachments/53871915/VMM+Tu ning+Tip+-+Proctecting+Comp+Memory.pdf?version=2 Whilst focused on Oracle, this PDF provides an interesting snippet on page 9: "Large hdisks are evil" for I/O performance! http://www.circle4.com/papers/PAI22.pdf Hope this helps Gregor -----Original Message----- From: u2-users-boun...@listserver.u2ug.org [mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Dan Goble Sent: Friday, 4 June 2010 6:51 AM To: U2 Users List Subject: [U2] Filesystem options cio for AIX 5.3 I am working with an AIX 5.3 system using Unidata 7.1.10 We are having some performance issues that are directly related to I/O. The files have been resized and brought down some of the I/O problems. In the past with some Oracle system I have had to administer ( I still prefer the mv world ), we used the cio options for mounting filesystems which allows for concurrent reads and writes. Has anyone tried this with Unidata or know of any pitfalls to doing so. Thanks in advance -Dan _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users -- Message protected by DealerGuard: e-mail anti-virus, anti-spam and content filtering. http://www.pentanasolutions.com Click here to report this message as spam: https://login.mailguard.com.au/report/1A12oPLg1S/6aKdA6wbF9XEaIVKtBO7mB/3.05 3 _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users