How to determine the value of parameter ncolumns for an N8000 striped file system

Publication Date:  2012-07-18 Views:  133 Downloads:  0
Issue Description
When the following command (in the first CLI line below) is executed to create an N8000 striped file system, error information is displayed:
N8000.Storage>fs create striped fs11 10g 8 pool3 stripeunit=1024 blocksize=1024
N8000.Storage>N8000 fs ERROR V-288-921 Unable to create fs fs11 due to either insufficient space/unavailable disk. Please run scanbus.
Alarm Information
None
Handling Process
Change the value of parameter ncolumns to an integer ranging from 2 to the available disk quantity.
Root Cause
According to error information that is displayed, this problem is caused by insufficient capacity or disk unavailability.
Check the format of the command of creating a striped file system.
fs create striped fs_name size ncolumns pool1 [disk1,...]* [stripeunit] [blksize]
The possible causes of the error information are as follows:
1. The size value is larger than the available space. It is verified that the remaining space is larger than 10 GB. This possibility is excluded.
2. The disk quantity is smaller than 8 specified in parameter ncolumns. It is verified that only six disks exist in pool1. Therefore, the cause is that parameter ncolumns is incorrectly specified.
According to the N8000 Series Clustered NAS Storage System Command Reference, the parameter description is as follows:
Parameter ncolumns specifies the strip quantity, which must be an integer no smaller than 2. If the number specified in parameter ncolumns is larger than the total number of available disks in pool1 [disk1,...]*, error information is displayed.
Note that the total number of disks here is the number of the disks that are mapped to hosts and added to the pool or the number of the disks in [disk1,disk2,...] specified by the command, not the number of the physical disks in the RAID group.
Suggestions
To ensure high performance for an N8000 striped file system, you are advised to specify the disks of different RAID groups for the pool or in the command.

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