20TB Storage System

[David Schultz]

On Fri, Sep 05, 2003, David Gilbert wrote:
> >>>>> "Poul-Henning" == Poul-Henning Kamp <phk at phk.freebsd.dk> writes:
> 
> Poul-Henning> In message <3F5647F3.5080502 at he.iki.fi>, Petri Helenius
> Poul-Henning> writes:
> >> fsck problem should be gone with less inodes and less blocks since
> >> if I read the code correctly, memory is consumed according to used
> >> inodes and blocks so having like 20000 inodes and 64k blocks should
> >> allow you to build 5-20T filesystem and actually fsck them.
> 
> Poul-Henning> I am not sure I would advocate 64k blocks yet.
> 
> Poul-Henning> I tend to stick with 32k block, 4k fragment myself.
> 
> Poul-Henning> This is a problem which is in the cross-hairs for 6.x
> 
> That reminds me... has anyone thought of designing the system to have
> more than 8 frags per block?  Increasingly, for large file
> performance, we're pushing up the block size dramatically.  This is
> with the assumption that large disks will contain large files.
> 
> ... but I havn't seem that, myself.  Large arrays that we run tend to
> have multiple system images (for diskless or semi-diskless operation)
> and many more thousands of users ... all with their usual complement
> of small files.
> 
> It strikes me that driving the block size up (as far as 1M) and having
> a 256 (or so) fragments might become appropriate.
> 
> We probably also need to address disks with larger block sizes soon,
> but that's another issue alltogether.

To that end, UFS2 is supposed to be able to support ``jumbo
blocks''.  The code for that isn't in the tree, but I presume Kirk
is working on it.