The need for weekly messages
EMC’s Symmetrix already knew this feature for a decade or so (or even longer), but since a few years EMC’s pushing customers to make every array to email home once a week so they can keep track of its pulse. And they’re not joking about its importance either, since once an array skips a beat, a severity 1 ticket is being created to get that fixed as soon as possible. EMC truly seems to care about the arrays they have running all over the world, so they’re indeed in good shape and being monitored actively.
We probably all know the following message:
Time Stamp 09/07/13 10:00:00 (GMT) Event Number 2011 Severity Information Host VNX13-AMSTERDAM-SPA Storage Array CKM00123456789 SP N/A Device N/A Description The array is alive. The heartbeat event is generated once every 7 day(s) on 10:00.
… or something that looks like this. But what if you actually have a bunch of arrays, varying from just a few to maybe douzens of them, and you do like to check the messages every week, just to see that they’re ok? Wouldn’t it be nice if all of them would send the heartbeat message at around the same time, on the same day?
There’s a command you can use to set the exact time on the commandline using NAVISECCLI, but exactly on what day isn’t an option. You can only set the time and once it’s set it will run every 7 days since the first time it ran.
Setting the weekday
And that gave me an idea: so what if I set the heartbeat email to a time that is yet to come? I tested it and it simply picks the first time that particular time criterium is met. So suppose I actually want the email to be sent on a Saturday at around noon? I figured that I’d have to set it AFTER noon on the Friday and since the noon on Saturday will be the first noon after I set it, it should work.
GMT versus the time in your timezone
I live in the Netherlands and with daylight savings time still active we’re 2 hours ahead of GMT. I didn’t realize this at first, so when I set the heartbeat mail to be sent at noon on the Friday, I waited for the email and it didn’t come. Now configuring this heartbeat email isn’t the only thing I had to do that day, so a few hours passed and when I checked on half past 3 in the afternoon or so I found out that the email was sent at 14:00, or 2PM as most Americans like to name that time of the day. So then I found out about the requirement of setting the email to be sent in GMT. So now I set it to 10:00 in the morning (10AM). Remember it’s still Friday afternoon.
This morning I came in the office and I checked the “The array is alive” messages and guess what? They’re now all being sent out to EMC (and me) on around noon on Saturday! Problem fixed!!
What about Sunday?
So what if you want the array(s) to send the email on a Sunday? Well, according to my findings you’d have to connect to the array on Saturday after the time you want to use for that Sunday and fire the command at the array. I hope there’s another way to set the heartbeat message, so the weekday can be included, but so far at least my method works.