Re: why 9 million TB for xfs

[pg_mh@xxxxxxxxxx (Peter Grandi)]

>>> On Fri, 25 Nov 2005 16:58:27 +0800, "meiyoutt"
>>> <meiyoutt@xxxxxxxxx> said:

meiyoutt> For xfs_sb.sb_dblocks is u64, so I don't know why xfs
meiyoutt> limit is 9 million TB.  I think 16 million of blocks
meiyoutt> in xfs, so why it's 9 million TB.

It is not as simple as that, and a filesystem cannot be larger
than the block device on which it is stored... Thus maximum
sizes depend on:

* Whether the kernel is 32 or 64 bit.
* Whether they are expressed in tibibytes or terabytes.
* Whether the kernel IO/cache subsystem uses signed or
  unsigned 32/64 bit 'int's.