topic asynchronous fs with sybase 12 in Operating System - HP-UX

asynchronous fs with sybase 12

Eric Guerizec — Mon, 21 May 2001 08:28:46 GMT

Hello,
We want to use asynchronous filesystem with sybase v12
on HPUX 64bits system.
I use vxfs with JFSOnline.
DO I have to set the kernel parameter fs_async
to 1? Is this sufficient?
Which will be the impact to change this parameter
on fs not used by sybase?
Thanks.

Eric

Re: asynchronous fs with sybase 12

eran maor — Mon, 21 May 2001 09:12:04 GMT

fs_async specifies whether or not asychronous writing of file-system data structures to disk is allowed. If no value for fs_async is specified, synchronous writes are used.

Synchronous writes to disk make it easier to restore file system integrity if a system crash occurs while file system data structures are being updated on the file system.
Asynchronous writes to disk can improve file system performance significantly. However, asynchronous writes can leave file system data structures in an inconsistent state in the event of a system crash. For more information about when to select synchronous or asynchronous writing

i m also sending you a doc about What are Synchronous and Asynchronous Writes

Re: asynchronous fs with sybase 12

Eric Guerizec — Mon, 21 May 2001 12:24:17 GMT

Thanks Eran,
When fs_async is set to 1, do there exist
specific vxfs options to put in /etc/fstab to minimize inconsistent file system
in case of crach?