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Is it true that on a Windows 2016 domain controller (bare metall installation), the disc write cache is turned off even if a battery-buffered RAID controller is installed and recognized by the system (by default after every reboot)?

(We don't have experience in Windows bare metall installations and there are contradictory informations on the internet)

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marsh-wiggle
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  • If you set the read/write cache in your controller's BIOS, how should Windows influence this? – Lenniey Nov 14 '18 at 16:45
  • @Lenniey In the properties of the hard disc (windows device manager) you can configure the write cache policy. On our test system (unbuffered cache) the cache can be enabled / disabled there, regardless to the bios settings. – marsh-wiggle Nov 14 '18 at 16:55
  • Ah OK. I don't exactly know what this setting _does_ in combination with a dedicated HDD controller with RAM and a BBU, but I do know that this setting is disabled by default to prevent data loss of the AD database in case of a power outage. – Lenniey Nov 14 '18 at 17:11
  • Yes, Active Directory attempts to disable the disk write cache when the service starts. Any disk that holds a database should never have write caching enabled. That includes Exchange and SQL Server. Disk write caching should also be disabled if there is an array controller cache. – Greg Askew Nov 14 '18 at 17:43
  • @GregAskew After reading this my question sounds a bit naive to me. I would humbly accept this as answer :-) – marsh-wiggle Nov 14 '18 at 18:04

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Yes, Active Directory attempts to disable the disk write cache when the service starts. Any disk that holds a database should never have write caching enabled. That includes Exchange and SQL Server. Disk write caching should also be disabled if there is an array controller cache.

Greg Askew
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