On 10/09/98 19:42:19 you wrote:
NetApp does not support NTP, so we must set the system time via periodic "rdate" commands. We have found that running rdate too often (or at the wrong time of day) can cause regularly scheduled jobs (such as scrubs) to be missed.
This is a known bug I discovered. I'd give you the BUGID if I had it. :)
Right now, we're setting the time three times a day, but that doesn't cut it. Some programs bitch that time is "going backwards" and other nonsense because the NetApp isn't synchronized with everything else. (*)
If your netapp is really drifting that much during the day, like a minute or more, then I suspect something is wrong with your netapp that needs to be address. Various factors in the past - old software releases, old SCSI cards, etc. - have contributed to clock drift. And sometimes, your clock is just bad. I think you should have support look into this and determine exactly how much your are drifting in a day and why.
(Note: It could drift farther during RAID scrubs than a minute. If your schedule your RAID scrub rarely and rdate after it, there should be no problems).
I'd like to know when NetApp cron jobs (other than scrubs -- I know when they happen) are scheduled, so we can run "rdate" more often, but without causing problems.
There are other periodic timed behaviors in a filer, like CIFS and WINS stuff, that are variable. I don't know if throwing off the software clock effects them - hopefully not. The only other major cron jobs you need to be aware of are the snap schedule (I think I've rarely if ever seen clock drift effect this) and the hourly statd message (and support email, whenever that is).
I would normally run rdate every, say, 15 to 20 minutes, and I would simply offset the times so it didn't run at the 0, 15, 30, or 45 minutes after (which is when a cron job would normally be scheduled).
What I'm trying to do (fix the time problem we're having) is really futile, of course. You can't synchronize crap with rdate.
It works as well as NTP for the granularity most people desire. I suspect in your environment, your needs are different, but don't tar and feather rdate for that. :)
Bruce