Syncronous writes

[Roberto Volsa]

Hello,
is HPUX 11i syncronous or asyncronous in it's write to disks? My disks are on a XP attached via SAN in fabric topology.

Thanks

[A. Clay Stephenson]

The answer is yes and yes; it depends on how a given application is coded. In reality, typically even with synchronous io the most that you know is that a write occurred to a physical disk's built-in cache with an array you know even less.

[Steven E. Protter]

If your application needs asynchronous access you may need to use the setprivgrp command to allow it.

setprivgrp group_of_app_owner MLOCK

It can be set in a file at boot.

/etc/privgroup

SEP

[Frank Slootweg]

Simple question, complex answer.

For starters, have a look at the options mentioned under "-o specific_options" in the mount_vxfs(1M) manual page ("man mount_vxfs") and follow the pointers from there.

Also applications can control this. See for example the description of "Synchronized I/O Flags" in the open(2) manual page ("man 2 open").