SAP Disk Defragment Tool

[Former Member]

Hi Everyone! Is there a built in tool that SAP has that can do disk defragment? I've searched all over the place but unable to find anything that SAP has built in or what SAP recommends. At the moment the built in Microsoft tool is not working at a level which we would like. Any advice would be appreciated! thank you!

[Former Member]

Hello Connie,

Disk defragmentation is not a good way to optimize IO performance, because the long downtime while the disk defragmentation is executed just doesnu2019t pay off.

There are probably recommendations from your database vendor on how to improve IO performance.

SAP Software relies on the DB for most information and therefore most IO operations will be to the database, not to the file system.

If you want to defragment a test system you could simply use the operation system tools to perform disk defragmentation. Windows 2000 and newer include a defragmentation tool called Diskeeper.

You should probably not try to defragment productive system or a SAN drive.

Regards,

Ventsi Tsachev

Technology Development Support (J2EE Engine)

SAP Labs, Palo Alto, Ca (USA)

[Former Member]

Hi,

Defragmenting a disk has nothing to do with SAP software. So SAP has no defragmenting utility.

Regards,

Olivier

[Former Member]

Thank you very much for your input! Are there any 3rd party programs that anyone would recommend that work well with SAP?

[Former Member]

Connie let me explain you this:

Data fragmentation in Hard Disks is produced when data in sectors are writen and after some time are deleted, then the hard disk itself whenever you try to write information in the disk it will try to fill the empty spaces it finds starting from first sectors and so on. Usually happens that a file uses more than 1 sector so if you have 3 free sectors between used sectors and you try to write a file that uses 4 sectors the electronics in the disk will fill those 3 free sectors and then the 4th sector will be writen somewhere else, this is call as disk fragmentation because the same file information is not next to each other. This is done by the disk or controller, not by SAP or Oracle.

Now we can tell that SAP has nothing to do with disk fragmentation because writing and deleting is done by hardware (with few exceptions) so you can use ANY software that you want to use for disk fragmentation. Be aware that disk fragmentations is important after thousands of hours. What is the percentage of fragmentation that you are so worry?

If you are in Windows then use the tools that comes with Windows as it is whell known that this are the best tools for defragmentation for NTFS or NTFS2.

The tool basically will move files in a way that they will be contiguous (in sectors) and it is supposed to improve performance but this is almost imperceptible so I wouldn´t worry much about this. If you want to improve performance then write here what is the problem you have and for sure you will get lots of info and answers.

[Former Member]

At the moment the built in Microsoft tool is not working at a level which we would like.

What exactly is your problem? Can you give us some more detail about your os version, the drive and files you are talking about? How is the drive formatted? Do you have one disk or something like a san storage subsystem?

Cheers Michael

[Former Member]

There was a problem with the OS level disk defrag system with drives over 1TB in size. We ended up buying the Diskeeper tool to defrag the disks. We were just making sure that SAP didn't have any issues with third party software since the SAP can be a little finicky at times. Thank you all for your input! I really appreciate it!