Hello Chris, Tuesday, June 27, 2006, 1:07:31 AM, you wrote:
CC> On 6/26/06, Neil Perrin <[EMAIL PROTECTED]> wrote: >> >> >> Robert Milkowski wrote On 06/25/06 04:12,: >> > Hello Neil, >> > >> > Saturday, June 24, 2006, 3:46:34 PM, you wrote: >> > >> > NP> Chris, >> > >> > NP> The data will be written twice on ZFS using NFS. This is because NFS >> > NP> on closing the file internally uses fsync to cause the writes to be >> > NP> committed. This causes the ZIL to immediately write the data to the >> > intent log. >> > NP> Later the data is also written committed as part of the pools >> > transaction group >> > NP> commit, at which point the intent block blocks are freed. >> > >> > NP> It does seem inefficient to doubly write the data. In fact for blocks >> > NP> larger than zfs_immediate_write_sz (was 64K but now 32K after 6440499 >> > fixed) >> > NP> we write the data block and also an intent log record with the block >> > pointer. >> > NP> During txg commit we link this block into the pool tree. By >> > experimentation >> > NP> we found 32K to be the (current) cutoff point. As the nfsd at most >> > write 32K >> > NP> they do not benefit from this. >> > >> > Is 32KB easily tuned (mdb?)? >> >> I'm not sure. NFS folk? CC> I think he is referring to the zfs_immediate_write_sz variable, but Exactly, I was asking about this not NFS. -- Best regards, Robert mailto:[EMAIL PROTECTED] http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
