6.x loosing record of free space after filesystem fills?

[Guy Helmer]

Oliver Fromme wrote:
> Guy Helmer wrote:
>  > I think we've finally found the cause of the problem - it wasn't just 
>  > occurring after heavy use, but was visible right after filesystem 
>  > creation!  We regularly built new filesystems with "newfs -U -O 1 -b 
>  > 65536 -f 8192"
>
> Why are you using those blocksize and fragsize settings?
> (If you store large files, then you should at least also
> decrease the inode density, using the -i option.)
>   
These settings were chosen to optimize I/O throughput for Postgresql on 
the theory that a 64KB block size would maximize disk throughput in the 
general case (especially for a RAID 10 system) and an 8K frag size would 
match Postgresql's page size.

I wasn't aware of any known regressions in 6.x regarding large 
filesystem block sizes...
> Some time ago, Joe Greco wrote:
>  > > the one unusual thing about the configuration is that the filesystem
>  > > we are attempting to build on is a 136GB ccd across 4 scsi disks with
>  > > the fsize=8192 and the bsize=65536 (it is mainly to be used for large
>  > > data log files):
>  > 
>  > FreeBSD doesn't support fsize/bsize so large.  There are ongoing issues
>  > within the filesystem code and VM code that will cause such filesystems
>  > to break under heavy load.  Matt Dillon also talked about this being less-
>  > than-optimal for the VM system from some technical points of view.
>
> It has been a while, and I'm not sure if there are still
> problems with those non-standard fsize/bsize settings, but
> I would definitely try to avoid them for production use.
>
> Best regards
>    Oliver
>
>   
Thanks,
Guy