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— | faq:misc12 [2011/04/30 17:33] (current) – created clemens | ||
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+ | [12] WHEN ARE THE SYSTEM MAINTENANCE WINDOWS? WHY THE LOW UPTIME? | ||
+ | | ||
+ | | ||
+ | 7 days a week, 365 days a year, 10 years a decade, 25 years a | ||
+ | | ||
+ | |||
+ | That being said there are unforeseen issues that can cause the | ||
+ | | ||
+ | |||
+ | 1. Hard Disk Crash - We have several spare drives, some of | ||
+ | them already plugged in and ready to be used. In the | ||
+ | best case scenario no maintenance window is required. | ||
+ | |||
+ | 2. Fire - In the case of fire all SDF machines must be shut | ||
+ | down unless the fire is an isolated occurance. | ||
+ | |||
+ | 3. Natural Disaster - In the Spring (Apr-May) we do get | ||
+ | affected by lighting strikes in our area due to heavy | ||
+ | thunderstorms. | ||
+ | the spikes and dips which allow SDF to run uninterrupted. | ||
+ | |||
+ | 4. Software Bug - This due crop up from time to time and are | ||
+ | usually related to system updates. | ||
+ | will let the public access machines lag behind NetBSD | ||
+ | development in order to test new releases in our lab before | ||
+ | subjecting the userbase to 'new bugs'. | ||
+ | |||
+ | 5. Routine and Scheduled Maintenance - Please read below. | ||
+ | |||
+ | 6. Hardware Component Failure - We have many spare machines, | ||
+ | some completely cabled up and ready to go at the flick of | ||
+ | a remote command. | ||
+ | unrecoverable, | ||
+ | minutes. | ||
+ | are hosted on the file server, the /tmp directory is exclusive | ||
+ | to each SDF client host. | ||
+ | |||
+ | | ||
+ | |||
+ | There is a weekly maintenance window on Sunday mornings beginning at | ||
+ | 02:00 AM until 03:00 AM. This windows is not always used and when it | ||
+ | is, it is used very briefly. 5 minutes prior to a shutdown or runlevel | ||
+ | | ||
+ | If you see this message alerting you to system maintenance, | ||
+ | save all open files and prepare to logout. | ||
+ | |||
+ | | ||
+ | the bboard in the board. | ||
+ | | ||
+ | / | ||
+ | |||
+ | | ||
+ | to take place. | ||
+ | | ||
+ | |||
+ | WHY THE LOW UPTIME? | ||
+ | |||
+ | | ||
+ | means that our goal is to have the servers answering at least 99.9% | ||
+ | of the time. In the 20+ years of service SDF has been able to meet | ||
+ | this goal. The most uptime you'll see on any given server will be | ||
+ | about 3 to 4 weeks. | ||
+ | This helps with clearing buffers, caches and other inconsistencies | ||
+ | that can occur as the systems run from cold or warm boot. Rather | ||
+ | than waiting for the system to fail due to kernel panic or a hang, | ||
+ | a warm boot is performed, during the weekly maintenance window, which | ||
+ | takes roughly 5 minutes or less. Keep in mind, this doesn' | ||
+ | | ||
+ | |||
+ | Why is this necessary? (aka "My box runs for years under my desk" | ||
+ | We too have very low usage non-public NetBSD systems that run for years | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | have to translate it long uptimes. | ||
+ | </ | ||
+ | |||
+ | [[misc|back]] |