24 TB UFS2 reality check ?

[Bakul Shah]

On Tue, 08 Jul 2008 13:01:50 PDT Julian Elischer <julian at elischer.org>  wrote:
> Juri Mianovich wrote:
> > I am about to attach 24 1 TB drives to a 3ware 9650SE-24 raid card
> and attach it to a FreeBSD 6.3-RELEASE system.
>
> > I am going to newfs that raw disk and turn it into one giant 24 TB
> UFS2 filesystem:

I think Jan is asking for trouble....  At the very least he
should consider mirroring or RAID5ing.

> You had better have a lot of memory available ot your processes to be 
> able to fsck this baby.. (it'd better be an amd64)..
> I don't remember the exact numbers but for 16k blocksize,
> it was something like 200MB ram for each 100GB of filesystem when 
> populated with 60KB files..
> (don't trust those numbers, do some testing (and let us know :-) )

I vaguely recall it was more like 700MB of memory per
Terabyte on a 50% filled UFS2.  Things may have improved
in the three years since I did that.  I don't recall the time
to fsck but it was pretty bad!  That was the main reason I
switched from UFS2.