We are using HP-UX Itanium version B.11.31 and this server is used for running Sybase database version ASE15.7. I would like to know how to enable Asynchronous IO at Operating System level.

I went through Sybase ASE and their suggestion is provided at this link.

Sybase Asynchronous IO

Appreciate your valuable input as which one should be chosen. I feel it should be "Enabling Asynchronous I/O for File System Devices."

Database is stored in the file system and they are VxFS(Veritas File System)

  • What are the plans for storing the database? On raw disks or in filesystems? – Jeff Schaller Mar 26 '19 at 13:20
  • @JeffSchaller Database storage is file system and not raw devices. – Learning_DBAdmin Mar 26 '19 at 13:48

Looks like the three pages are somewhat poorly titled.

"Enabling Asynchronous Disk I/O HP-UX" page describes the installation of the asynchronous I/O driver. It would be definitely needed if you wanted to use asynchronous I/O with raw devices, but you aren't planning to do that.

I found this link to an old HP Knowledge Mine document that confirms that the asyncdisk driver is for raw disk access only.

"Enabling Asynchronous I/O for File System Devices" page describes a pair of HP-UX kernel tunables as a prerequisite, but the actual task seems to be how to enable Sybase to use HP-UX asynchronous file I/O, assuming it's available.

"Enabling Asynchronous I/O for File Systems" page describes how to make sure HP-UX can provide asynchronous file I/O. It says "you need to have OnlineJFS installed". Basically, this page should have been a part of the "prerequisites" section of the previous page.

  • I checked with Sysadmin and seems 3rd option i.e. changes pertaining to VxFS is already there at server. so, if I got your point correctly, it should be change only for 2nd point i.e. change pertaining to kctune. – Learning_DBAdmin Mar 26 '19 at 15:06
  • 1
    Exactly. I don't really see why Sybase has separated the 2nd and 3rd points, as they clearly belong together. – telcoM Mar 27 '19 at 12:14

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