Managing external storage with the storage_setup script

You can add external SAN or NFS storage to your appliance using the storage_setup script.

Important: The script allows you to manage two types of storage, SAN and NFS. Note that:
  • IBM makes no claims as to the speed/performance/stability characteristics of external storage. Various factors (such as data center networking and quality of components that are used in the storage device) determine the performance. Use enterprise class hardware with top tier components where available for the best experience.
  • NFS isn’t recommended for any native Db2 applications, and should be used as file storage only.
  • SAN storage is supported for all IAS models except M4002-001. With M4002-001, you can only use NFS.

Prior to adding or removing external storage to the appliance, the system state must be stopped by using the apstop command. The code will check to ensure that the appliance is in the proper state prior to executing.

SAN requirements
If you run LC fiber to the appliance, you can choose to plug into either:
  1. 1+2 nodes via patch panel
  2. All nodes via direct cable connection
If you choose option 2, you can't install the fiber yourself. Instead, you need to contact IBM to install the cables in accordance with rack level compliance. IBM (via PMR or sales representative) will direct you to the relevant parties to obtain a Statement Of Work (SOW) and schedule the installation process.
In both cases, all the involved nodes need to be the same in cabling (1 or 2 cables per node) and LUN presentation (all nodes must see the same LUN).

Multipathing (multiple links to each block device) is required.

SAN expansion requirements
You need to add a new LUN instead of expanding the existing. In a case of current LUN expansion, the SAN is erased and re-created to see the larger size. The new LUN must be added to all chosen nodes, similar to the initial setup. Only adding new LUN preserves existing data.
NFS requirements
NFS server must support the showmount functionality. Your NFS storage server must have the following UID:GID mapping for the users: 
USER:GROUP              UID:GID
APUSER:IBMAPADMIN       6500:2001
BLUADMIN:BLUADMIN       5001:3000
However, depending on NFS server configuration, permissions may change to be any number of users, including NOBODY:NOBODY and ROOT:ROOT.
  1. Check the permissions on the added folder:
    [apuser@sail57-t03-n3 ~]$ ls -lahd /opt/ibm/appliance/storage/external_mnt/NFS/backups
drwxrwxr-x. 8 root root 4.0K Mar 11 13:27 /opt/ibm/appliance/storage/external_mnt/NFS/backups
    If they are not apuser:3000, work is needed on the NFS server side to enable proper ID mapping.
  2. After fixing the permissions on the server, you can run the storage_setup --reset_permissions command to set proper apuser:3000 permissions again: 
    [apuser@sail57-t03-n3 ~]$ storage_setup --reset_permissions
See /var/log/appliance/platform/xcat/setup_storage.log to watch its progress.
changing ownership...
Done
changing permissions...
Done
  3. Ensure that the permissions are set successfully:
    [apuser@sail57-t03-n3 ~]$ ls -lahd /opt/ibm/appliance/storage/external_mnt/NFS/backups
drwxrwxr-x. 8 apuser 3000 4.0K Mar 11 13:27 /opt/ibm/appliance/storage/external_mnt/NFS/backups
When adding NFS to IAS, the storage_setup script displays only valid folders, and filters out invalid folder paths (such as root /).
The script checks whether you have firewall access to the designated NFS server allowed. The NFS server must use the default ports and these must be open.