Wondering about the SLA being offered by your host/provider. Here is what it means in daily, monthly, and annual downtime.?5 9’s looks near impossible doesn’t it? Some servers take longer than that to reboot so a standby is required to?achieve?that and you have to fail over to it prior to rebooting anything. On top of that you need to consider sessions and moving those between hosts regardless of whatever app you are using. That’s a lot of moola for any company so it’s important you consider what is truly acceptable in terms of down time. I think most?companies?would fit in the 3 9’s and that isn’t an easy task to accomplish either. Unless you have a static app that never changes, never needs to be updated, and requires no?management. Those exist right?
|Acceptable uptime percentage||Downtime per day||Downtime per month||Downtime per year|
|95||72.00 minutes||36 hours||18.26 days|
|99 (two nines)||14.40 minutes||7 hours||3.65 days|
|99.9 (three nines)||86.40 seconds||43 minutes||8.77 hours|
|99.99 (four nines)||8.64 seconds||4 minutes||52.60 minutes|
|99.999 (five nines)||0.86 seconds||26 seconds||5.26 minutes|