Date: Fri, 10 Jan 2014 15:18:43 +0100 From: Attila Nagy <bra@fsn.hu> To: Dmitry Morozovsky <marck@rinet.ru>, Steven Hartland <killing@multiplay.co.uk> Cc: 'freebsd-fs' <freebsd-fs@freebsd.org> Subject: Re: What does ZFS write when nothing should write there? Message-ID: <52D00143.9060603@fsn.hu> In-Reply-To: <alpine.BSF.2.00.1401101728030.24613@woozle.rinet.ru> References: <52CFA0B6.7090109@fsn.hu> <alpine.BSF.2.00.1401101707430.24613@woozle.rinet.ru> <52CFF18F.5040809@fsn.hu> <29BFE2939CF14317A149D6C2D68D9A8E@multiplay.co.uk> <alpine.BSF.2.00.1401101728030.24613@woozle.rinet.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
On 01/10/14 14:29, Dmitry Morozovsky wrote: > On Fri, 10 Jan 2014, Steven Hartland wrote: > >>>>> I've created 6 zpools, each of them with zpool create -m /data/A dataA >>>>> mirror >>>>> daX daY. >>>>> The machine has nothing running except sshd and my shell. >>>>> >>>>> Yet, I see this in gstat: >>>> [snip] >>>> >>>>> 0 88 0 0 0.0 82 573 4.1 9.0 da5 >>>>> 0 89 0 0 0.0 83 573 4.8 9.8 da6 >>>>> 0 87 0 0 0.0 81 573 2.6 5.7 da9 >>>>> 0 89 0 0 0.0 84 573 3.0 6.7 da10 >>>> Did you turn off atime? >>>> >>> No, but how does it matter? >>> The process list is the following: init, getty, sshd, csh and the pool is >>> completely empty. >> With atime on each time you access a file it will update its "atime" >> hence causing writes. >> >> We use atime=off at the pool level on all machines to avoid that >> zfs set atime=off <pool> > BTW, it seems that ZFS updates atime of some inodes (root one?) on every kernel > update thread invocation even when completely empty -- is it correct behaviour? > Because there are no files, it must (?) be the root. But at this frequency?
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?52D00143.9060603>