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System performance, and RAID BIOS settings.

Article ID: 1283
Last updated: 26 Apr, 2013
Views: 6671
System performance, and RAID BIOS settings. Rating: 6.0000 / 10
Votes: 3
Posted: 16 Jun, 2011
by:
Updated: 26 Apr, 2013
by: Rafinski G.

The most probable reason for very bad system performance is the RAID controller's cache being disabled!

In most cases there is no need for any investigation. The first thing to check is if the RAID Cache is ON, and enable it if it is not.

Some RAID controllers without a BATTERY BACKUP UNIT on board switch the cache OFF by default!

Some RAID controllers need to set more than just one single parameter in order to enable the cache.

For example, RAID controllers with LSI chipset have following options:
 
      Default Write Policy:         Write Through; Write Back
      Cache Policy:                    Cached; Direct
      Disk cache policy:            Enabled; Disabled
      Read Policy:                      Readahead; None; Adaptive
 
In order to get the cache enabled, please go to RAID Controller BIOS and make sure following options are selected:
 
      Default Write Policy:   Write Back
      Cache Policy:              Cached
      Disk cache policy:      Enabled
      Read Policy:                Adaptive << in some cases Readahead can be better >>
 
Also, please read our blog post about the RAID Cache:
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Also listed in
folder Troubleshooting -> Hardware -> Hardware RAID problems

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