January 27, 2011 at 8:36 pm
Comments posted to this topic are about the item Does It Count?
January 27, 2011 at 11:10 pm
I do believe that scheduled maintenance windows should not be counted in the uptime guarentee because of the same reasoning mentioned in the editorial - scheduled maintenance windows are planned and committed in advance to the customers. Besides, most often scheduled maintenance does not mean that the whole system is down - it's more of an inconvenience because the load balancing is not as expected or the performance is degraded, but the system is still functional on a backup/failover setup.
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January 28, 2011 at 1:07 am
More important than whether or not planned maintenance is included in downtime is: that it is clearly and unambiguously agreed.
From the customer's perspective, consider which is preferred:
- A system with 15% downtime due to planned maintenance.
- Or a system with 1% downtime due to unforseen events.
Finally, when negotiating an SLA it shouldn't be a problem to factor planned (note the word here implies foreknowledge) maintenance into the equation.
If you expect to be down 1% of the time due to planned maintenance, then agree on 2% total downtime.
January 28, 2011 at 2:07 am
I wholly agree with craig 81366. So long as it is agreed, understood and documented then it doesn't really matter whether it's included or not.
January 28, 2011 at 2:09 am
My internet company promises 99.9% uptime. Imagine if they had scheduled outages and that was weekly and I couldn't use my internet during that time. It would be annoying enough that I would get a different service provider.
Scheduled outages should be included in the SLA when calculating your up-time. If you have to take the system down and the system cannot be used, then it impacts your performance.
January 28, 2011 at 5:51 am
Downtime is downtime, scheduled or not. So IMHO it ought to be included.
January 28, 2011 at 6:02 am
In a 24 hour period if your equipment is down at anytime....then it is down. It does not matter to the clock why it is down, its just down.....If you are a service company offering 4/9 uptime time, I would seriously rethink your uptime policy, because maintenance needs to be completed on all equipment. There is a difference between scheduled maintenance and unscheduled maintenance, and a good custodian of that equipment takes both into consideration when managing his assigned equipment. As business owners the SLA should include both instances of downtime in the calculations of advertised uptime. However we all understand that a level of marketing is required to sell a product and a figure like 99.99% uptime is a better sell than 89.99% uptime. That maybe a different debate though....
Happy Friday to all!
January 28, 2011 at 6:02 am
I would definitely include scheduled downtime as downtime.
If backup servers, etc., can keep things up for customers/employees/etc., then it's not downtime for the database, which is what really matters. I don't bother tracking server downtime, just database downtime.
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January 28, 2011 at 6:06 am
Downtime should include all outages, planned or unplanned. The whole point of an SLA is for setting expectations of users so it should be measured from the perspective of the person using the system. If they are unable to use it, then the system is down.
If you distinguish between planned and unplanned, what do you do when a planned 30-minute maintenance window turns into 2 hours of downtime because something goes wrong during the maintenance?
The only motivation to not include scheduled outages is to make your numbers look better than they actually are.
January 28, 2011 at 6:06 am
Thinking in even more detail, I believe the definitions vary between on-premise and hosted deployments.
In my opinion, hosted environments need to include both the scheduled & unscheduled downtimes in their uptime guarentee. However, on-premise deployments should be exempt from this because a scheduled downtime may only end up affecting a fixed subset of users.
I have mostly worked on on-premise systems and from what I have seen, users are not affected much or can use their backup plans (eg. "offline" mode, or reschedule their weekly off) if they know about a downtime in advance.
Thanks & Regards,
Nakul Vachhrajani.
http://nakulvachhrajani.com
Follow me on
Twitter: @sqltwins
January 28, 2011 at 6:35 am
Ever go to an ATM that had a message "Down for system maintenance"? Maintenance windows were tollerated in the past when they were an accepted requirement of having computers. This, along with not encrypting data, single points of failure, and numerous other practices are no longer acceptable to customers who expect 24x7 response.
January 28, 2011 at 6:40 am
EricEyster (1/28/2011)
Ever go to an ATM that had a message "Down for system maintenance"? Maintenance windows were tollerated in the past when they were an accepted requirement of having computers. This, along with not encrypting data, single points of failure, and numerous other practices are no longer acceptable to customers who expect 24x7 response.
Actually yes. Every saturday night from 2ish to 5ish.
January 28, 2011 at 6:48 am
Absolutely, it should count. Downtime of any kind will affect end users whether they are scheduled or not. If a company is not counting it toward total downtime, then they can just mask bigger issues within those "maintenance windows" and essentially adhere to any SLA level.
January 28, 2011 at 6:54 am
It should be counted -- always. It is the only way to compare apples to apples. Someone could have 3% scheduled downtime a month and another could have 1%. If you want a measure of how well you are doing, measure everything and then try to reduce it overall. Shouldn't you also be trying to reduce your scheduled downtime?
January 28, 2011 at 7:34 am
Should scheduled maintenance be counted against your downtime SLA?
I try to avoid any controversy by making sure the vendor has included language in the SLA that specifies whether scheduled maintenance is counted against downtime or not. That way when I review downtime statistics I understand what's included and can easily determine the severity and whether the SLA is being upheld or not. Along with whether there are problems that need to be addressed or not.
Any ambiguity on what's included makes it difficult to interpret the statistics. You could end up looking for problems that aren't there or ignoring problems that need addressing.
When your handed downtime statistics, you need to know what you're looking at.
Dave
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