Why does zfs produce a batch of writes every 30 seconds on opensolaris b134 (5 seconds on a post b142 kernel), when the system is idle?
On an idle OpenSolaris 2009.06 (b111) system, /usr/demo/dtrace/iosnoop.d shows no i/o activity for at least 15 minutes. The same dtrace test on an idle b134 system shows a batch of writes every 30 seconds. And on current opensolaris bits, on an idle system, I see writes every 5 seconds. The periodic writes prevents that the disk can enter power save mode. And this breaks the /etc/power.conf autoS3 feature. Why does zfs have to write something to disk when the system is idle? > > Putting the flag does not seem to do anything to the > > system. Here is my power.conf file: > ... > > autopm enable > > autoS3 enable > > S3-support enable > > Problem seems to be that all power managed devices > must be at their lowest power level, otherwise autoS3 > won't suspend the system. And somehow one or more > device does not reach the lowest power level. ... > The laptop still does not power down, because every > 30 seconds there is a batch of writes to the hdd drive, > apparently from zfs, and that keeps the hdd powered > up. > > The periodic writes can be monitored with: > > dtrace -s /usr/demo/dtrace/iosnoop.d -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
