On 07/19/12 19:27, Jim Klimov wrote:
However, if the test file was written in 128K blocks and then
is rewritten with 64K blocks, then Bob's answer is probably
valid - the block would have to be re-read once for the first
rewrite of its half; it might be taken from cache for the
second half's rewrite (if that comes soon enough), and may be
spooled to disk as a couple of 64K blocks or one 128K block
(if both changes come soon after each other - within one TXG).
What are the values for zfs_txg_synctime_ms and zfs_txg_timeout
on this system (FreeBSD, IIRC)?
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