Re: [RFC][PATCH 1/11][take 2] add new mkfs option to create ext4 filesystems

Andreas Dilger
2007-06-25T21:59:26Z

On Jun 25, 2007 20:24 +0530, Aneesh Kumar K.V wrote:
> Why would one need variable descriptor size. Right now we have only two
> descriptor sizes right (32 and 64 ). Can't we figure out
> the descriptor size we should use by looking at the partition size ? What
> is that i am missing ?.

Because one may want to expand an ext4 filesystem over 16TB after format
time, and this would require a 64-byte descriptor. In ext4 the descriptor
is almost completely full already (to deal with BIG_BG changes, and possibly
large blocksize changes), so we may even need 128-byte descriptors soon.

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.