topic Re: umount and option -s in Operating System - HP-UX

umount and option -s

Eric SAUBIGNAC — Fri, 08 Apr 2011 11:50:42 GMT

Bonjour,

Yet an other silly question : umount has a "-s" option. But what does it stand for ?

I can't find any documentation about it. But it exists :

root@ockham:/#umount

usage: umount [-V] [-v] [-f] [-s] { special | directory }
umount [-F FStype] [-v] [-f] [-s] [-h host] -a

You can also find some comments, very few in fact, about -s in MC/ServiceGuard package configuration files ...

I guess it has the same behaviour than the same "-s" option in fsck : no sync is done when unmounting a FS.

Could someone point a document that will confirm or counter my understanding ?

Thanks in advance

Eric

Re: umount and option -s

Patrick Wallek — Fri, 08 Apr 2011 12:04:24 GMT

What version of the operating system do you see this on? On my HP-UX 11.11 system, there is no '-s' option.

Re: umount and option -s

Eric SAUBIGNAC — Fri, 08 Apr 2011 12:57:05 GMT

HP-UX 11.31, Patrick.

But as far I remember "-s" option was also mentioned in package configuration files with HP-UX 11.23. Not sure with 11.11, but I think it was too.

Re: umount and option -s

Ismail Azad — Sat, 09 Apr 2011 06:11:35 GMT

Hello eric,

Looks like it's a really rare option and it is even more strange that it's hardly documented anywhere even in the manual page and there is_an_example with the -s option in the pkg configuration file!. And the only one point I could find is that -s with umount gives_better_performance.

Regards
Ismail Azad

Re: umount and option -s

Eric SAUBIGNAC — Mon, 11 Apr 2011 11:37:11 GMT

Bonjour Ismail,

"Better performances". That's the heart of my question : better performances vs what ?

Eric

Re: umount and option -s

Ismail Azad — Mon, 11 Apr 2011 16:42:16 GMT

Bonsoir eric,

Well that performance vs. what is a pretty difficult question as this mysterious option is documented in microscopic places. Well what I understood is this option when used in a SG environment with a package having many filesystems in turn increases the performance of the environment and looks like that is the most useful scenario in which the -s option is used and yes, I understand why you relate it to the -s option on fsck as the source says both fsck and umount should be used with the -s option. But exactly how -s accomplishes something related to "better performance" is a mystery to me but I TOTALLY understand why the no sync wild guess... :)

Regards
Ismail Azad

Re: umount and option -s

Eric SAUBIGNAC — Tue, 12 Apr 2011 12:01:01 GMT

Well, with no certainty, I will assume that the deal is "perfomance vs reliabilty". As usually.

So I will not use the umount "-s" option.

Thanks every one.

Eric