Re: was Four people troll - now meandering off elsewhere
On 04/03/14 08:41, Miles Fidelman wrote:
> Scott Ferguson wrote:
>> On 03/03/14 23:28, Fred Wilson wrote:
>>> On Mon, 03 Mar 2014 12:52:40 +1100 Scott Ferguson
>>> <scott.ferguson.debian.user@gmail.com> wrote:
>>>
>>>> Which is fine for you, and I can understand and appreciate
>>>> that, for my own personal computers my sentiments are similar.
>>>> However my business purposes involve meeting SLAs so reboots
>>>> once or twice a year can cost a lot of money - so in those
>>>> circumstances a few minutes makes a lot of difference. Perhaps
>>>> that's not something you care about - or it's just convenient
>>>> to ignore until your bank/phone/stockbroker/shopping is
>>>> interrupted as a result.
>> http://en.wikipedia.org/wiki/Service-level_agreement
>> http://en.wikipedia.org/wiki/High_availability#Percentage_calculation
>>
>>
>>
>>
>>
When you pay for a five nines SLA, perhaps for your business web
>> site hosting, or what your bank/business pays for their trading
>> platform that means we must be offline a *total* of less than 5
>> and a half minutes *a year*. That's begin reboot to all services
>> restarted. Failure to do so results in penalties that can *very*
>> quickly exceed the annual support contract. While a great deal of
>> effort and planning goes into *shifting loads* so that reboots
>> don't affect production - things don't always work to plan, so good
>> plans allow for that. Meaning systems must be designed to reboot in
>> less than the allowed downtime - with a safety margin. If we can
>> shave a few seconds off reboot time we can shave a large amount off
>> the support contract price, with the possibility that those savings
>> are passed on to the consumer.
>
> Anybody who is counting on a fast reboot to maintain a 5 nines SLA
> is simply nuts.
Agreed.
What do you call people who don't read what they reply to? The
same thing you call people who "know" about areas of technology they
have had no experience in?
> that's what redundancy and high-availability configurations are for.
Yes. And they get tested, as do all the components. Which means
rebooting is something that doesn't just happen on production systems.
It all adds up to lost productivity. To paraphrase Oliphant
"extrapolation is not a human strength"
>
> Personally, I'm a lot more worried about what's going to break when
> we move to Jessie and systemd - and all those things I might have to
> reconfigure. That involves serious time, effort, and dollars. And
> that's before the things that will break intermittently. I still
> shudder every time I think of the impact udev had on our operations,
> before we got the subtleties figure out. (Note: at the moment "we" =
> "me" and sleepless nights that impact other work.)
Anybody who is counting on stability and not running stable is, I won't
say nuts, but I would say "challenged", and sure to have an
"interesting" time. :) That said your use cases are unlikely to be mine
- and I don't know what I don't know, so I won't presume to dictate your
needs.
We don't move to stable until it's been stable at least a year (so the
move to Wheezy has only been recent, in many cases we still run
old-stable) - anything less give insufficient time for testing. But the
developers need at least two years lead time before we can even sit down
and discuss support contracts that entail more substance than trying to
nail snot to the wall.
>
> Miles Fidelman
>
Kind regards
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