17 Mar
2012
17 Mar
'12
8:03 p.m.
On Mar 16, 2012, at 4:29 PM, John R Pierce pierce@hogranch.com wrote:
and with LVM, an entire PP block has to be copied, right? those are generally much larger than file system blocks, 4MB to 16MB, I believe? thats kind of brutal.
Actually the larger the block the less of a load. It moves more data in a single operation and if another update on that same block occurs it no further COW operation is needed.
The alternative would mean lots of small IO operations which would hit the disk's max IOPS faster then 4-16MB blocks would hit a drive's max throughput.
-Ross