System information

Troubleshooting
6-5
4. It takes very long time for the web GUI to respond my commands
The web GUI is presented by browser but its contents are generated by the storage processor, which need also process
I/O request as well as other maintenance tasks. You might experience slow GUI when the I/O access is very heavy.
Please reduce the workload or stop some background tasks.
Bad hard disks or bad blocks could cause long response time of web GUI, because some system information is retrieved
from or written to hard disks. When it takes a long time for hard disks to complete an I/O request, the web GUI would
freeze to wait for the I/O completion. Please use hard disk diagnostics utilities to identify the problematic hard disks and
remove them.
5. Some pages in the System Management menu are not viewable
The RAID controller offers two levels of administration access right. If you login as a user (username: user), you are
restricted to read-only web GUI pages. Login as administrator (username: admin) allows full-function management and
access to all pages.
6. No display or response on the LCD
If your RAID system is capable of redundant-controller configuration, the LCD can be managed by only one of the two
controllers at a time, and you need to use LCD hot keys (see 3.2.5 Hotkeys on page 3-4) to choose a controller to
control the LCD.
6.6 RAID Configuration and Maintenance
1. 2TB limitation and how to choose sector size
Because of 32-bit logical block addressing (2^32 x 512 bytes = 2TB) used by the MBR-based partition table and by the
host operating systems, like Windows 2000, Windows XP 32-bit, and Linux 2.4.x kernel, the maximum size of single
partition or logical drive is limited to 2TB size. You can use logical volume management (LVM) software to aggregate
multiple LUNs.
For Windows above to work around the 2TB limitation, choose bigger sector size of a LUN (see 2.6.7 Storage
provisioning on page 2-25). However, you cannot use dynamic disk in Windows for the LUN with non-512B sector size,
and your data will be lost if you change the sector size of a LUN. The table below shows the capacity correlated with
sector size.
The latest partition table GPT (GUID Partition Table) and modern operating systems, like Windows XP 64-bit, Windows
2003 server SP1, Windows 2008 server, Windows Vista, and Linux 2.6.x kernel, support 64-bit logical block addressing
without the 2TB limitation. Using 512B as the sector size (default) is fine.
2. Failed hard disk interrupts the background maintenance tasks
To avoid unwanted overloading and risk, the reconfiguration task of a disk group is paused and the disk scrubbing is
aborted when a hard disk of the disk group goes offline. If there is a spare disk or the failed hard disk is replaced, the
reconfiguration can be resumed after the disk data rebuilding is done. For disk scrubbing, you’ll need to restart it
manually.
3. Failed hard disk interrupts the background maintenance tasks
To avoid unwanted overloading and risk, the reconfiguration task of a disk group is paused and the disk scrubbing is
aborted when a hard disk of the disk group goes offline. If there is a spare disk or the failed hard disk is replaced, the
reconfiguration can be resumed after the disk data rebuilding is done. For disk scrubbing, you’ll need to restart it
manually.
4. Hard disk shows Unknown state
The configurations on the hard disks cannot be recognized by the controller. You need to erase the configuration
information on the hard disks for your RAID system to use the hard disks.
If you need not to retain the data and the configurations on the hard disks, you can clear configurations on the hard disks
(see 2.10.1 Restoring to factory settings on page 2-48). You may also turn off the On-line Array Roaming option (See
2.7.16 Miscellaneous on page 2-37). With that, the RAID controller will not check the stored configuration information of
hard disks and see any newly installed hard disks as hard disks without configurations. You may remove and then re-
install the unknown hard disks to the system (either manually or by GUI, 2.6.1 Hard disks on page 2-16). The hard disk
state will return to “Unused” state.
If you need your data and configurations, please contact your system supplier for solutions.
Table 6-1 The capacity correlated with sector size
Sector size 512B 1KB 2KB 4KB
LUN Size 0 ~ 2 TB 2 ~ 4 TB 4 ~ 8 TB 8 ~ 16 TB