Re: 64-bit block sizes on 32-bit systems

Dave Kleikamp (shaggy@austin.ibm.com)
Wed, 28 Mar 2001 08:53:03 -0600


My turn to chime in.

JFS was designed around a 4K meta-data page size. It would require some
major re-design to use larger block sizes. On the other hand, JFS could
take advantage of 64-bit block addresses immediately. JFS internally
store the block address in 40 bits. (Sorry, file size & volume size are
both limited to 4 peta-bytes on JFS.)

At the rate that storage hardware and requirements are increasing,
increasing the block size is a short-term solution that is only going to
delay the inevitable requirement for 64-bit block addressability. There
is a practical limit to a usable block-size. Someone threw out 64K,
which seems reasonable to me.

-- 
David Kleikamp
IBM Linux Technology Center
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/