Summary: 12TB GEOM stripe, newfs, then fsck: cannot alloc 768053748 bytes for blockmap

[Alex Zbyslaw]

Frantisek Rysanek wrote:

>Thanks a lot to Mr. Zbyslaw.
>  
>
You're welcome.

>A local friend has suggested to increase the block size to 
>newfs, or something along those lines - essentially to
>decrease the FS overhead and the size of the "blockmap".
>I haven't tried that but I guess it sounds reasonable
>- may make sense on machines where you just can't get
>enough RAM or are not willing to grant it all to a single
>process.
>  
>
It ought also make sense if you are serving up *large* files (didn't you 
say video/audio?).  I'm planning to do some tests at some point to see 
what difference different block/fragment sizes make to performance, but 
haven't found the time yet.  I don't have anything on your scale (23Gb 
of document database pales into insignificance against 12Tb :-) ) but I 
haven't found any specific numbers anywhere.

If you're interested, check out the -b and -f options to newfs.  The 
defaults are 16k/2k.  Decreasing the number of inodes would definitely 
make sense (see -i).  The -N option ought to show you what would happen 
without actually doing anything.

--Alex