Figure 86 Initial Deployment Of Meta Cache; Table 69 Expanded System Volume - Fujitsu ETERNUS DX S5 Series Design Manual

4. NAS Functions
NAS System (NAS Volume Management)
Note
During the design phase
To use the Eco-mode function for TPPs that include NAS volumes, move the system volumes to a different
TPP. The Eco-mode function does not work for a TPP that contains system volumes. System volumes can
be moved by using RAID Migration.
During the configuration phase
• Copy operation suppression (volume protection) cannot be set for system volumes.
• The status of the controller (CM) is "Maintenance" until system volumes are created. When NAS user
volumes and system volumes are created, the status of the controller (CM) changes to "Normal".
■
Expanded System Volume
To use the NAS audit log function, create expanded system volumes for each controller in advance. Volume
names can be set arbitrarily.
The following table shows the type, capacity, and usage of the expanded system volumes.
Table 69 Expanded System Volume
Type
cm0-nas-ex-sysvol
cm1-nas-ex-sysvol
Expanded system volumes are required for saving the NAS audit logs. For the creation procedures, refer to "Audit
Log Setup" in "Configuration/Operation Guide (NAS)".
■
System Management Area
Each NAS volume must have a system management area of approximately 300GB. This area is the metadata
area that is used by the system for managing file system information.
■
Meta Cache
For the NAS file system, information for managing metadata, which is file system information, is deployed in the
cache memory of the controller (CM) for each NAS volume to seed up access. This is called meta cache.
Meta cache is deployed in either CM#0 or CM#1 for each NAS volume. Immediately after a NAS volume is
created, the meta cache is deployed in both CMs equally.
Figure 86 Initial Deployment of Meta Cache
Meta cache
If maintenance work is required due to problems such as errors detected in the NAS volume, the meta cache
may be unevenly deployed in one controller. The ETERNUS DX supports the function that releases the
unbalanced state. Your maintenance engineer may ask you to execute this function during maintenance. For
details on the function, refer to
Capacity
1GB – 4TB
1GB – 4TB
CM#0
Meta cache
NAS volumes
ETERNUS DX
"Meta Cache Distribution" (page
Usage
Expanded system volume for CM#0
Expanded system volume for CM#1
CM#1
Meta cache
Meta cache
168).
165 Design Guide