Easy Fixes

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This page is meant for a short description of all those little emergencies that will make an inexperienced sysadmin panic, where anybody who's met them before will go "shrug, this is a cynch".
 
This page is meant for a short description of all those little emergencies that will make an inexperienced sysadmin panic, where anybody who's met them before will go "shrug, this is a cynch".
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== Changing Defaults ==
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=== Raid-5 journals and bitmaps ===
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As of October 2017, it's been disallowed to run raid-5 with both a journal and a bitmap. It's pointless to do so, and causes problems with race conditions in recovery. So if an upgrade makes your array stop running, the fix is to assemble the array with the option "--update=no-bitmap"
  
 
== Hardware Troubleshooting ==
 
== Hardware Troubleshooting ==

Revision as of 23:14, 19 October 2017

Back to Timeout Mismatch Forward to Replacing a failed drive

This page is meant for a short description of all those little emergencies that will make an inexperienced sysadmin panic, where anybody who's met them before will go "shrug, this is a cynch".

Contents

Changing Defaults

Raid-5 journals and bitmaps

As of October 2017, it's been disallowed to run raid-5 with both a journal and a bitmap. It's pointless to do so, and causes problems with race conditions in recovery. So if an upgrade makes your array stop running, the fix is to assemble the array with the option "--update=no-bitmap"

Hardware Troubleshooting

Replacement Controller Cards

If you think your controller is faulty, and have replaced it with a spare you had lying around, make sure the controller and drives are compatible! Some SATA-II controllers cannot handle drives over 2TB.

Boot Problems

Centos Emergency Mode

Centos (and presumably other distros) has an emergency mode. Typically such modes suppress module loading, ignore fstab, and a whole host of other potentially problematic features.

Of course, this also will suppress a load of features you want like bringing up your raid array. Try manually doing all the features you expect boot to do for you.

Back to Timeout Mismatch Forward to Replacing a failed drive
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