Accusys ExaRAID GUI - Manual (Page 245)

Troubleshooting
6-2
• Voltage failure or error
• Power supply failure or error
• Fan failure or error
• Temperature failure or error
• BBM failure or error (when BBM is connected)
• Disk SMART warning
• Disk bad block over threshold warning
• Disk group with degraded logical disk and no disk for rebuilding
• Disk group with faulty logical disks
• UPS failure or error (when UPS control is on, see 2.9.4 UPS on page 2-
70)
• Controller failure or removed
• Dual controllers fail to boot up because of configuration conflict
• Controller failback cannot proceed
6.3 Performance Tuning
Performance tuning is always not an easy job because it requires in-
depth knowledge of hardware and software. This section offers a few
guidelines for you to identify performance problem sources and to do
improvements. However, the system performance depends on not only
the RAID system but also the capability of all software and hardware
components along the I/O path. Please contact your solution providers
to choose field-proven configurations.
1. Understand the I/O workload pattern
Understand your workload before configuring the RAID for your hard
disks. Most applications can be classified into two types of workload:
transaction (database or file server) and stream (video/audio or backup/
archival). The former tends to be random access with variable IO size,
and the former is sequential access with large IO size. Read the manual of
your applications to find the suggested RAID configurations, or check the
Appendix when choosing the RAID configurations.
2. Adjust the controller performance parameters
The RAID system is equipped with many parameters that allow you to
gain excellent performance and also poor performance when poorly
configured. Basically delayed write and read ahead option should be
turned on, and cache unit size should be set according to your IO size.
But if you are unsure about how the parameters work, please choose the
performance profile in the Quick Setup menu (see 2.5 Quick Setup on
page 2-20) according to your workload or leave all parameters as
default.