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In Search of the "Perfect" Pager Rotation? 70

Posted by Cliff from the time-share-beeper dept.
jSpectre asks: "At my new job the Unix SA team has increased from 5 to 7. We're trying to work out a new, rotating on-call schedule and everyone has 'perfect' but conflicting ideas. Twelve weeks on and 6 off, 25 weeks on and 10 off. I thought someone out there must have come up with the perfect formula given N number of people you could rotate through the weekdays and weekend most efficiently. My google and web searches have come up with nothing. Does anyone know of a good formula/solution? The requirements are this, we have 7 people (but the forumla should ideally apply to N people) who should rotate through the weekdays (a 24 hour period) and the weekend (a 48 hour period). There is a desginated primary and a secondary person. They should be on for a few weeks and off entirely for a few. Sound like a good thesis/research problem for someone? By the way, Google comes up with a lot of people's schedules if you search for pager rotation. Tisk tisk."
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In Search of the "Perfect" Pager Rotation? More

In Search of the "Perfect" Pager Rotation?

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  • 7 people, 7 days in a week . . . (Score:5, Funny)

    by Mordant ( 138460 ) on Wednesday July 09, 2003 @10:44PM (#6404979)
    Hmmm - maybe we're onto something . . . ;>
    • Well no. Because we want one person to cover the whole weekend. We also want some time off where you aren't on duty at all. So rotate thru the days and then off entirely for a period of time. But thanks.
      • I don't get it. Why not just rotate in a queue format?

      • Acually, counting the weekend as ONE day works! You then have 7 people and 6 days, which can work out really well. (damed lameness filter won't let me use day numbers, so I'll try for good names)

        Day = Person
        Monday = Alice
        Tues = Bob
        Wed = Carol
        Thurs = Doug
        Fri = Ed
        Sat & Sun = Frank
        Mon = George
        Tues = Alice
        Wed = Bob
        Thurs = Carol
        Fri = Doug
        Sat&Sun = Ed

        and follow the pattern. What's nice about the pattern is that if your the person stuck with the weekend, you are totally off the next w

  • I love it (Score:2, Funny)

    by Anonymous Coward
    /. editors keep posting questions from real people with real jobs asking about help with their real jobs. Penis envy?

  • Some of us... (Score:5, Funny)

    by infernalC ( 51228 ) <matthew@mellon.google@com> on Wednesday July 09, 2003 @10:52PM (#6405022) Homepage Journal
    ...don't worry about pager rotations because our datacenters never have failures, you insensitive clod!

  • In search of the perfect lotto number... (Score:5, Funny)

    by $exyNerdie ( 683214 ) on Wednesday July 09, 2003 @10:53PM (#6405027) Homepage Journal
    I want to win the Powerball® jackpot which is estimated at $250 million.
    Does anyone know of a good formula/solution? The requirements are this, I want to win this Powerball® jackpot (but the forumla should ideally apply such that out of the N times I play, I should win at least N-1 times). Sound like a good thesis/research problem for someone? By the way, Google comes up with a lot of pages [google.com] if you search for lucky Powerball® numbers. Tisk tisk.

  • Auction it (Score:5, Interesting)

    by A nonymous Coward ( 7548 ) * on Wednesday July 09, 2003 @10:55PM (#6405031)
    Give everyone points per week, either same for everybody or based on seniority. Then set up a schedule in advance, whoever has the most points gets the duty. When duty is taken, points are removed. People can of course volunteer for duty, and if multiple ones do, low points get first choice. Allow points to go negative.

    Or something like that. I'm sure it could be an interesting exercise designing the points system and implementing a web page to handle it.

    One more thing, you need some kind of deadline, no changing your mind within a week of duty. But if you get someone to swap, allow that.

    Now if you are going to pay for the duty, you want the weekly points awarded based on how much different shifts cost. Maybe factor in seniority also.

    • Re:Auction it (Score:2, Interesting)

      by mcdrewski42 ( 623680 )
      Interesting idea with the points.

      I'm assuming with the pager that people are paid for being on call. I know in my company that wasn't the case and all 'N' employees eventually got jack of the idea until payment was forthcoming.

      We rotated on a purely week-by-week basis. Swaps were normally handled amicably, but if you couldn't find anyone to fill in when you wanted them, and you were not on actual annual leave, bad luck.

      You know, that sounds almost so self-evident I might patent it as a business process
      • I'm assuming with the pager that people are paid for being on call.

        If that were the case, I'd imagine that people would volunteer to be on call, in order to get more $.

        More than likely, they're salaried like we all were when I was in IT. It makes better sense to have IT personnel salaried (from a business standpoint) because there may be times that they have to be at the office for an ungodly amount of time.

        Case & point: I got to work at 7AM regularly. We were moving our entire datacenter from one b
        • Try working a Disaster Recovery exercise.

          48 hours, non-stop.

          When I was an OT-collecting employee, that was WONDERFUL.

          Now that I'm salaried, I get The Big Screw. Work 48-hours for us in for free.

          Yuck.
        • If that were the case, I'd imagine that people would volunteer to be on call, in order to get more $.

          Agreed. This is largely the reason why the 'swaps' were handled fairly amicably. It's easier to find someone who's willing to take on the job if there's a payoff and not just a drawback.

          I'm salaried too (we all were). I don't mind putting in some extra hours for special occasions (ie: your datacentre move), but this was on-call support for a production billing system - 24x366. There's a big difference
          • BUT, in addition to our datacenter move, we did an on-call support rotation, 24x7 per person, every four weeks. One week on, three off.

            I'd never get myself into a position where I was the only support guy for 24x365. Not without some SERIOUS incentive!

    • Re:Auction it (Score:5, Interesting)

      by Eneff ( 96967 ) on Thursday July 10, 2003 @12:17AM (#6405295)
      ding ding ding!


      mod points just expired, though. Damn!


      I'd actually put a twist on the idea... Instead of losing points, have people gain points for doing these duties. (You start at a base 50 points, for example, then auction down for each 4 day/3 day or 5 day/2 day shift.)


      now here's the rub... you reverse auction for desirable days/weeks off. (Christmas, Thanksgiving, et al) People use accumulated points to bid for it off. The two that bid the least are primary and secondary, respectively. Those two would then get some percentage of the points bid.

      So, for example, I'd have no problem working Christmas and Easter, but I'm taking the two weeks surrounding my birthday off. (This could conflict with Easter, but you get the point.) I'd also bid for the week containing labor day, for example.

    • You may want to read up on scheduler algorithms... the traditional Unix scheduler is similar to this. Substitute "nice value" for "seniority", and adjust the PRI based on pages received rather than cycles consumed, and volunteers are essentially using yield, and you've got a pretty decent starting point.

  • This Could Really Burn Some on Holidays (Score:4, Insightful)

    by TheWanderingHermit ( 513872 ) on Wednesday July 09, 2003 @10:58PM (#6405049)
    Maybe you could work out a schedule based on the calendar year. The current one could seriously frustrate some people if they are on through the entire holiday season. Thanksgiving, Christmas, and New Years could easily come within 6 weeks of each other. It might be entirely possible some people are on through this whole time and others are off that entire time. If it's not balanced off the next year and some of the same people have to stay on call a 2nd year through that time, I would think it could lead to hard feelings.

    While the holidays may not effect your business, they do have a storng emotional effect on most staff and it might help to set up the schedule to treat people fairly not just in regular time on/time off, but also in holiday time. For example someone who works Christmas or a 3 day weekend might get an extra week or weekend off some other time.

    I've never had to deal with this in the tech field, but when I was in property management, I know anyone on call over holidays always felt at least a little frustrated, but at least they knew they all had to deal with it more or less equally.

  • An idea (Score:3, Interesting)

    by blate ( 532322 ) on Wednesday July 09, 2003 @11:06PM (#6405071)
    Let's start with the assumption that you don't care if you're on-call, so long as you never get paged to do something during non-business hours.

    A simple system that would work for N people might be the following:

    1. Number the people 1..N (or 0..N-1 if you're feeling geeky).
    2. The pager starts with person 1. If you need a secondary or tertiary (sp?), then assign to persons 2, 3, ...)
    3. If person j takes the call passes the pager on to the next unallocated person in the list, who takes on j's priority (i.e., primary, secondary, etc.); if the primary takes the call and you have secondaries, etc., the secondary becomes the primary and the next unallocated person on the list becomes secondary.
    4. Goto 3 (couldn't resist)

    Assuming that calls are evenly distributed, then you only have to take a call every N*(call inter-arrival time) units of time.

    You could change around the "who gets primary next" rule in various ways.

    Assuming that you don't get more than one call on a weekday or over a weekend, this system should be reasonably fair.

    • Re:An idea (Score:4, Insightful)

      by TheWanderingHermit ( 513872 ) on Wednesday July 09, 2003 @11:35PM (#6405103)
      Let's start with the assumption that you don't care if you're on-call, so long as you never get paged to do something during non-business hours.

      Speaking as someone who had a real jerk for a boss and was on call for 11 months at one stretch, I don't think that's a valid assumption. While it seems like there's no problem unless you're called, being on call can be a stressful experience. It means you can't go out of town and you have to be aware that any activity you plan may be interrupted. For me, it meant I had a full spring, summer, and fall where I could not go on one single long (20 miles or longer, which put me out of quick "response" range) bike ride, which is something I love to do.

      There's another problem with this overall idea, as well. If you move in an unpredictable rotation like this, then you never know if you're going to be on call for an upcoming weekend. It means you basically can't plan on going away for a weekend until Friday. If you have a lot of friends and an active life, that is unacceptable.
    • Forgot one...

      5) Profit!!!

      back to lurking...

  • Perfect... no such thing (Score:3, Insightful)

    by MerlynEmrys67 ( 583469 ) on Wednesday July 09, 2003 @11:39PM (#6405109)
    Why not get the group of N together, and then see what they think...

    Make it even easier say $x a day for pager coverage (more for weekends) plus pay for call ins. That makes it easier... I don't have a life, need more money, I volunteer more often/take extra shifts. I have a real life, don't want as much extra work... I don't volunteer as much. Shifts that aren't covered are simply rotated through (still getting the extra bucks)

  • Get more holidays! (Score:3, Insightful)

    by ptaff ( 165113 ) on Wednesday July 09, 2003 @11:55PM (#6405174) Homepage
    Supposing the density of the calls is not very high, use a two-person/week scheme.

    Person 1: Primary from midnight to noon, secondary from noon to midnight;
    Person 2: Primary from noon to midnight, secondary from midnight to moon;

    Rotate each week (week 2: person 3-4, ..., week 4: 7-1, ..., week 7: 6-7). After 7 weeks, each person will have worked 2 weeks. Not so bad, only a 22% uptime is needed.

    And for an odd N (in your case 7), you automatically shift morning/night in each iteration.

    Seems easier that way too, you don't have to remember "are we thursday and it is really between 6am and 11h30am?".

  • Simple formula! (Score:2, Interesting)

    by shfted! ( 600189 )
    This is really easy! The length of the period of rotation is exactly x (number of persons) weeks long. At week 1, person 1 (primary) and person 2 (secondary) are on for Monday through Sunday. At week n, person n (primary) and person n+1 (secondary) are on. At week x, person x (primary) and person 1 (secondary) are on.

    The length of a week is used so everyone gets an equal amount of time. Everyone is on call 2/x number of weeks. Shifts can be swapped easily, just be careful that primary and secondary aren'
    • That almost works, and if he hadn't mentioned distinguishing from weeks from weekends would work
      W1 P1/A2
      WE1 P3/A4
      W2 P5/A6
      WE2 P7/A1
      W3 P2/A3
      WE3 P4/A5
      W4 P6/A7
      WE4 P1/A2
      W5 P3/A4
      WE5 P5/A6
      W6 P7/A1
      WE6 P2/A3
      W7 P4/A5
      WE7 P6/A7
      Obviously for any more than 4 people this will work out. for less than that... you will end up being on call all the time anyway. And of course if you have 4 people, you will have to figure something out to alternate weeks and weekends.
  • 1 week on, $numberofemployees - 1 off
    manager intervenes in cases where a person is about to work the the second holiday in a row, in which case the person being screwed trades with the person before him in the rotation.
    Apply appropriate further perturbations in cases where the holidays worked differential exceeds 2.
    Incidentally, in case somebody's looking for a really good unix admin to cover a holiday or something...?

  • best "rotation" (Score:3, Funny)

    by kasper37 ( 90457 ) on Thursday July 10, 2003 @01:45AM (#6405643) Homepage
    I've found that the best rotation is the everyone-gets-paged-and-if-you-don't-see-it-fixed- within-a-few-minutes-find-a-terminal rotation.

  • Randomly rotate every 44 hours (Score:3, Funny)

    by infonography ( 566403 ) on Thursday July 10, 2003 @02:22AM (#6405749) Homepage
    Use a ten sided dice to pick the person, remember to roll behind your dungeon master / System Admin screen.

    I like to use Buzz word bingo to select the next victim. Today "Beowulf cluster" is an instant critical hit.

    Or try These [google.com]

  • Not really a rotation, but.... (Score:3, Interesting)

    by krangomatik ( 535373 ) <rfujikawa@yahooL ... m minus math_god> on Thursday July 10, 2003 @02:29AM (#6405769)
    We all carry nextel phones or pagers and get text messages from our alerting system when things go down. When I see something go down and I'm somewhere I can vpn in I'll usually do so and check to see if any of my coworkers on actively vpn-ed in and give them a beep to see if they are already working on the problem and see if they need any help. If there isn't anyone looking at it and I'll usually jump on in and get to work and the next person who takes a peek will see me and we'll talk they'll get a feel for what's going on, the extent of the problem, etc. This works pretty well for us (we are small, 10 person group and pretty much know where each other are the evenings/weekends). We also have an answering service that has a formal 'on call' list, so if a customer calls with a problem they'll just call down the list until someone answers. We rotate the list around every quarter, or therabouts, so the 'primary' person changes. I often volunteer for the top spot on the list because I'm pretty flexible and don't have a wife/kids and don't mind being called. This works out well because if I'm not able to fix it we have a list they can call down and everybody pulls their weight so no one really feels bad if they have to hand it off down the list now and then. I'm guessing that since you are looking for a more formal schedule that this sort of 'loose' system may not be the right answer for you, but it may be the right answer for others. We have separate call out lists for some more specialized systems (oracle, router folks, mainframe, telecomm) so that when there is a problem with a specialized system you get the more experianced people first. Our managers are also at the bottom of the list, so if all else fails the call will go to a person who has a complete phone list and a good idea of where people are so they can start call people's alternate numbers and what not. This system also allows for quite a bit of flexiblity people. Our 'tradespeople' (aka union) side of the house where there are MOU's or something relating to off hours support has a more formal policy, but they also have financial incentive (time and a half type stuff) for being on call, so there isn't usually a lack of people willing to be on call. One thing that we have considered, that may work for you, is dumping our answering service for a PBX based application. That way customers could be routed through a menu tree (yeah, people just love those...) that would identify the area of the their problem and then page out the people on call for that area. You can tie something like that in with your calandering/scheduling system so that only people who have time marked as free are paged. You would have to incorperate some sort of checking to ensure that you had at least a primary and alternate for any given time, but it should be doable. I am coming from a shop where people are generally will to be on call when possible, so we don't often run into a situation where someone has to give up something just to be on call, so YMMV with this type of system.

  • The way we do it... (Score:4, Insightful)

    by onjay ( 27282 ) on Thursday July 10, 2003 @02:40AM (#6405797)
    This is a perpetual scrum in medical residency, too. We can't do back-to-back calls, which makes it harder than, "You cover this weekend."

    0 - Get a big ass calendar with holidays and some pencils. Decide how many days/year each person will have to work. Break them down into 4 or so categories: weekday, friday, weekend, holiday are ours. Friday is annoying because you can't go out but not as bad as an 24h (weekend/holiday) day. If weekends are light, you could just have "weekday" and "friday + weekend" categories. Anyway, share around evenly.

    1 - Holiday parity is a good place to start. Noone wants to get screwed both xmas and new year's. Ask for preferences and nail down someone for coverage for these and Labor day, the 4th, T-day, etc. They can trade later.

    2 - Map out the conferences and people's known vacation blocks, anniversaries, exams, etc.

    3 - Some people haven't adapted to a totally random fill pattern of coverage, so give people a choice of contiguous blocks/easy to remember patterns (M/W for the month of ___) or irregular blips.

    4 - Schedule the parts where many are out of the office with whatever it takes. Subtract these and the holiday days from the totals each person has to work. Schedule the pattern-desiring people and people with evening classes/outside commitments/inability to show up if on a random schedule. Again revise the totals.

    5 - Start marching through at the beginning, rotating through the N people available. Keep running track of the fridays/weekends, do a little stagger to keep the weekends from being the same person on the same day, and it will start filling out.

    6 - Think outside of the month to fit those last days in. You don't have to fill months contiguously or in date order. If there is a new employee, it may be best to slack off a bit on them (no weekends) at first until they fill out their KB; this gives you some flex.

    N - Nothing you can do will make the perfect schedule. You have to have one master list that is the last word, and on which everyone must record their trades. Leftover days are best distributed to the people who took the least holiday days or the dues-paying new hires.

    N+1 - Write some open source software to do this. Acrimony might be less, and the legibility would be better for sure.
  • Have everyone involved in the rotation pick a few important holidays. Maybe two or three each. Then factor in all Major Holidays that may have been missed. Lets say 7 people and 30 holidays, schedule your weeks/days on and weeks/days off so people don't work too many holidays in a row. (eg: Thanks giving, Christmas, New years) Print up a couple years as a sample to see if its fair. Adjust as needed. Allow people to trade weeks/days so they can work around vacations, weddings, giving birth etc...

  • This problem has already been solved. (Score:4, Funny)

    by MarkusQ ( 450076 ) on Thursday July 10, 2003 @04:11AM (#6405996) Journal
    This problem has already been solved. You should be searching under more general terms (e.g. "fair scheduling algorithms") rather than problem specific terms like "pager rotation," that's all.

    For example, let's say you have N people working (and all are interchaingable, to start with). That means that each of them should be on call for K = 1000/N milliseconds out of every second (on average). Provided there are less than 500 people to be scheduled, you can accomplish this by rounding K to an integer (for the case where there are more that 500 people to be scheduled, either schedule them for one millisecond each, or go to a finer grained time-base). One important point to remember is that you must resource lock the call to the person in << K ms to avoid race conditions (which can garble text messages and result in an annoying high-pitched noise if two or more people try to return the call simultainiously and get multiplexed--

    Hot damn, my run just finished.

    G'night all...

    -- MarkusQ

  • Auction it... (Score:1, Interesting)

    by Anonymous Coward
    Low bidder gets stuck with the job, and second lowest bidder gets secondary. All the rest have to pay the third lowest bid to the person stuck with the job.
  • Whatever. Do what my team lead used to do. Every time we paged him when he was on rotation, we'd realize the pager was in his desk drawer. Well, every time except the one time when he said "I'm too drunk to come in."

  • Try a DA Form-6 (Score:5, Informative)

    by oni ( 41625 ) on Thursday July 10, 2003 @08:49AM (#6406550) Homepage
    The Army had to solve this problem eons ago in order to have rotating guard and staff duty schedules. Thier solution is the DA Form-6. Look it up. It has all the features you specified.

    • DA Form 6 form does not answer his question on HOW to allocate the schedule. It is just a pre-printed sheet to write down a schedule once it has been established.

      Leave it to the government to turn what is essentially a sheet of lined paper in to a formal, named and itemized military-spec piece of equipment.

      How much you think a pad of those costs?

      • DA Form 6 form does not answer his question on HOW to allocate the schedule.

        Correct, but not very helpful.....

        How much you think a pad of those costs?

        Nothing. ALL Army forms are available in PDF format. The advantage of a piece of paper is that you don't need a computer to operate it. This comes in handy in places like foxholes, which typically lack electricity.

        FWIW, AR 220-45 tells you HOW to use the form. This took me, oh, 10 seconds to locate via google. FWIW, here's [army.mil] a PDF copy of the reg. Of
        • Of course, I'm not a cynic who condemns all things military because they are military.

          That was my thought exactly when I read his comment. That, and the thought that he is a loser.

          What unit are you in?

      • DA Form 6 form does not answer his question on HOW to allocate the schedule.

        Yes it does. The HOW is the accompanying regulation. See redleg's post below.

        It is just a pre-printed sheet to write down a schedule once it has been established.

        no it's not. The regulation - the HOW - is part of it.

        Leave it to the government to turn what is essentially a sheet of lined paper in to a formal, named and itemized military-spec piece of equipment.

        It's clear to me that you have no clue what you're talking

  • What's with all these complex calculations?!? (Score:3, Interesting)

    by dustpuppy ( 5260 ) on Thursday July 10, 2003 @10:12AM (#6406961)
    In my team which has 5 people, we do one week of on-call, rotated around the team each week.

    It means you go on call 1 week in 5.

    Simple to understand, simple to implement and no hassles. People swap individual days with other SA if they have some pressing engagement which they need to attend.
    • Here! Here!

      Why does the piecewise it difficult? This isn't pilot scheduling!

      I just set up the same thing here. 7 people, you have it from Thursday to Thursday (people can then take Mon/Fri off!). I did add one thing though... If it rings two nights in a row, it goes to the next person.

      Jason Pollock
    • We do this to ... its the easiest way to split things up.

      In our rota we sit down every three months or so and work out between the people who are on the rota who wants to do which week, which works ok as long as the people on the rota are reasonable, (out of the last 5 years I've covered Christmas and New Year 4 times but then I'm a geek who never goes out and I volunteered to cover then so that people who had children didn't need to be on).

      We do allow the people on the rota to decide between themselves

  • I work in a team of 4 admins, and we have two types of pager duty, day and night. The day pager is from 8AM to 5PM. The night pager covers 5PM to 8AM and all day Sat and Sun. We rotate day pager on a daily basis, and night pager on a weekly basis. You cannot have day pager on the same week you have night pager.

    This scheme works out good. We all end up with an even amount of day pager duty in a month, and we each get 13 weeks of night pager duty per year. If a holiday falls on a weekday, the night pager pe

  • Graveyard shift? (Score:3, Insightful)

    by cliveholloway ( 132299 ) on Thursday July 10, 2003 @02:37PM (#6408770) Homepage Journal

    Errr, this might be too obvious, but have you asked if anyone wants to work the graveyard shift?

    That would remove 90% of the problem.

    I don't know about your situation, but most groups of geeks contain one or two that are night owls. Why not pay them a small premium to work nights? A lot cheaper than overtime.

    .02

    cLive ;-)

  • put a bunch of holidays in a hat (twice, once for primary, and once for secondary) give each holiday a value (prim, secd) Christmas - 5,3 New Years - 5,3 4th July -5,3 Easter - 3,2 Thanksgiving - 3,2 Labor Day - 2,1 Memorial Day - 2,1 Presidents Day - 2,1 everyone draws one holiday Everyone must end up with at least 6 pts of holiday er something... This wouldn't solve the whole thing, but it would fix the holiday problems...
  • You don't mention how many on-call at once? Is there a primary contact and a secondary contact?
    At my last job, there was a primary contact, who would receive the initial call. If, within a given time period, there was no response, the secondary person would be called.
    How about giving the pagers to two people each week - if you've got seven people, you could have time off between the time spent as primary and secondary, or just make everyone do two weeks of on-call (one as the primary contact, one as the se
  • Riiiight!. It's almost unateinable to get 3 people to agree on where to have dinner.

    You wanna make 7 techs to agree on a schedule?

    Do it by "Military Junta". Get a Manager and 2 elected members of the team to decide on the of the proposals submitted by the team.

    Then, blame failure on the Junta and praise those who abstained to vote. :-P
  • In my group we have about a dozen people to rotate the pager through. Right now, each takes it for a week at a time - so you're only on-call about 4 times a year. We hand over the pager every Monday morning.

    We just picked someone at random to be the "first" and then went through the list of people in the group alphabetically, copied/pasted 3 times (to get about a year's worth) and then overlaid it on a calendar. If someone has a week they know will be bad, they can swap with someone right away. Holiday
  • Speaking as a manager, I think it's interesting that there's a large focus on the "fairness" of the schedule. In my experience, there are a lot more issues to be concerned about. In order, I think they are:

    1) How responsive do you need to be? Generally the shortest time period you can rely on is 15-30 minutes - if you need faster responses, you better keep people on-site 24-7. But there's a big difference between being "on-call" with a response time of 2 hours versus being "on-call" with a response tim

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