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[T Series]An Rhel 5 Inherent Defect Led to a Significant Storage Performance Fluctuation

Publication Date:  2012-07-19 Views:  403 Downloads:  0

Issue Description

Product and version information:

  • S5500T V100R001 V100R002
  • S5600T V100R001 V100R002
  • S6800T V100R001 V100R002
  • Application server operating system: Linux rhel5u3_x86-64 2.6.18-128.el5
  • FC switch: Brocade 5100

The storage device and the application server were on an FC switch connection network as shown in Figure1.
    Figure 1 FC switch connection network


When an application server was performing small data block sequential reads to a LUN, the storage performance fluctuated significantly, between 18% and 20%.

Alarm Information


Handling Process

Contact Red Hat technical support personnel for assistance.

Root Cause

We ran the same test on a peer vendor's storage device, and the same symptom occurred.
It is concluded that the significant storage performance fluctuation was due to an inherent mechanism defect on the Linux rhel5u3_x86-64 2.6.18-128.el5 application server.


Storage performance fluctuates when the rhel5u3_x86-64 2.6.18 operating system and the ATTO-FC82EN HBA are both used in a SAN network environment. Performance-demanding services such as VOD do not fit in such an environment.