[rhn-users] Using tmpfs

[Corné Beerse]

Charith Perera wrote:

> Hi everyone,
> 
> I've run into a problem with using a temporary file system for Sybase. This 
> may turn out to be a Sybase issue, so if you think that is the case then 
> please point it out immediately. In either case any solutions are definitely 
> welcome.
> 
> I've put a line in /etc/fstab as follows:
> 
> tmpfs /dev/sybase_tempdb  tmpfs mode=700,rw,size=3G 0 0
> 
> As suggested by this guide : http://www.peppler.org/FAQ/linux.html#q1.19
> 
> 
> When we attempt to initialize a sybase device for tempdb the following error 
> is returned. When we use an ext3 partition everything goes fine. 
> 
> dopen: open '/dev/sybase_tempdb/tempdb.dat', Invalid argument
> udactivate: error starting vidtual disk 2
> 
> 
>>From the sybase website at 
> http://www.sybase.com/detail/printthis/1,6907,20336,00.html I found this:
> 
> "Sometimes Sybase Adaptive Server Enterprise reports disk I/O errors when 
> current disk analysis shows there are no such errors."
> 
> My question to you is, is there a difference from an application's point of 
> view if a filesystem is tempfs or ext3? My initial guess was that it should 
> be transparent to the application, but now I doubt that or I'm not setting up 
> the temporary filesystem properly. I'm about to create files as the same user 
> being used by the application.

No, there is no difference for the app if only the filesystem changes, except 
for not available capabilities (think writing to a iso-filesystem...). However: 
if the filesystem is mounted with different options, like your 'mode' setting, 
it is likely that the app does see it.

Hence, try without the 'mode=700' part, better jet: only use the "size=3G" ( or 
more).