Open-E Knowledgebase

System performance, and RAID BIOS settings.

Article ID: 1283
Last updated: 26 Apr, 2013

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:
This article was:   Helpful | Not helpful Report an issue

Article ID: 1283
Last updated: 26 Apr, 2013
Revision: 1
Views: 7271
Posted: 16 Jun, 2011 by Rafinski G.
Updated: 26 Apr, 2013 by Rafinski G.
print  Print email  Subscribe email  Email to friend share  Share pool  Add to pool
Also listed in
folder Troubleshooting -> Hardware -> Hardware RAID problems

Prev     Next
How many CPU cores and RAM recommended?       Performance Testing with DSS V6 for your NIC's and Volumes

The Knowledge base is managed by Open-E data storage software company.