Disk drives for integrated Windows servers

Integrated servers do not have their own disk drives. i5/OS™ creates network server storage spaces within its own file system and integrated servers use them as if they were normal hard disk drives.

For an integrated Windows server to recognize an integrated server disk drive (network server storage space) as a hard disk drive, you must link them together. You must create a disk drive before you can link it. See Create an integrated server disk drive and Link a disk drive to an integrated server. After you create and link a new integrated server disk drive, it appears as a new hard disk drive to the integrated server. Then you must format it before you can use it. See Format integrated server disk drives.

Disk drives can be linked to servers in one of the following ways:

1. Fixed (static) disk drive links allow disk drives to be linked to the server using user specified link sequence positions. The order that the server sees the drives is determined by the relative order of the link sequence positions. The server must be varied off when adding a fixed (static) disk drive link.
   Note:
   
   Static drive links are not used for iSCSI attached xSeries® servers.
   
2. A cluster quorum resource disk drive link is used to link the cluster quorum resource disk drive to the servers in the cluster.
3. Cluster shared disk drive links allow a disk drive to be shared among clustered integrated servers. A shared drive can only be linked to nodes that share a common quorum resource drive. Drives of this type are available to all nodes that are joined together by the links of the cluster quorum resource. Each node has access to the shared drives under the control of Windows Cluster services running on each node.

   Note: Drives that are linked as shared should be linked to ALL nodes that are clustered together.

4. Dynamic disk drive links allow additional disk drives to be linked to an integrated server using dynamically assigned link sequence positions. The disk link sequence position is assigned dynamically at the time that the disk drive is linked to an active server. The disk link sequence position can be specified, but it is not used until the server is restarted. The integrated server can either be shut down or active when adding a dynamic disk drive link.

When a non-iSCSI integrated server is started, it sees the disk drives in the following order:

1. Statically linked disk drives.
2. Cluster quorum resource disk drive.
3. Cluster shared disk drives.
4. Dynamically linked disk drives.

For iSCSI attached servers, the cluster quorum disk appears at the end of the list of disk drives. Dynamically linked disks and cluster shared disks can be intermixed.

Within each of these link type categories, the disks appear in the order of their user specified link sequence positions. When dynamically linking a disk drive to an active server, the new disk drive appears following all other linked disk drives.

The following table shows the iSeries™ virtual disk drive features supported for various types of server network server descriptions (NWSDs) with i5/OS V5R4 or later.

Disk features supported

Feature	NWSD type5 *WINDOWSNT or *IXSVR with OS type *WIN32	NWSD type5 *ISCSI with OS type *WIN32
Number of fixed (static) links	16	0
Number of dynamic links	16	631
Number of cluster quorum links	1	1
Number of cluster shared links	15	611
Maximum number of virtual disks that can be linked to the server	48 with clustering2; 32 otherwise	64 with clustering2; 63 otherwise
Maximum capacity per virtual disk	1000 GB	1000 GB
Maximum total virtual disk capacity, assuming 1000 GB per disk	46.9 TB with clustering2; 31.3 TB otherwise	62.5 TB with clustering2; 61.5 TB otherwise
Can link virtual disks while the server is active?	Yes Exceptions: fixed links	Yes Exceptions: dynamic links 1-2
Can unlink virtual disks while the server is active?	Yes Exceptions: fixed links, disk can not be part of a volume set, disk can not be a volume mounted in a directory	Yes Exceptions: dynamic links 1-2, disk can not be part of a volume set, disk can not be a volume mounted in a directory
Virtual disk format types allowed when linking3	*NTFS, *NTFSQR, *FAT, *FAT32, *OPEN	*NTFS, *NTFSQR, *FAT, *FAT32, *OPEN
Virtual disk access types allowed when linking	Exclusive update, shared update4	Exclusive update, shared update4
Disk links requiring exclusive update address type	All fixed disk links and all dynamic links	All dynamic links
Disk links requiring shared update address type	Cluster quorum link and all cluster shared disk links	Cluster quorum link and all cluster shared disk links

1. For iSCSI Windows servers, the dynamic and cluster shared disks use the same sequence position range and can be intermixed. The combined total number of dynamic and cluster shared disk links is 63.
2. Windows server clustering requires use of Microsoft® Cluster Service (MSCS) to control access to the shared disks in the cluster.
3. See the Create NWS Storage Space (CRTNWSSTG) command help text for a description of the format types.
4. When multiple servers link a disk using shared update, only one server can actually have write access to the disk at any point in time. For example, on Windows servers, Microsoft Cluster Service (MSCS) is used to control which server in the cluster has write access to the disk.
5. See the Create Network Server Desc (CRTNWSD) command help text for a description of the NWSD types and the associated operating system (OS) types.

Network server storage spaces can reside in either the i5/OS system disk pool (ASP 1) or a user disk pool. You can copy one disk drive to another to move it to a different disk pool.

After a network server storage space has been created and linked to an integrated server, you must format it from the Windows console. You can choose from between three types of disk formats. You will probably choose NTFS since it is the most efficient and secure format. Partitions formatted with NTFS can be up to 1,024,000 MB. Another format type is FAT-32. Partitions formatted with FAT-32 can be from 512 – 32,000 MB. The oldest format type is FAT. The maximum possible size for a FAT partition is 2,047 MB. The predefined installation source drive partition (D), which must be in FAT format, is therefore limited to 2,047 MB.

Network server storage spaces are one of the two types of network storage that integrated servers use. Integrated servers can also access resources on i5/OS that an administrator has shared with the network by using iSeries NetServer™.

The IBM® iSeries integrated server support installation process creates several disk drives that are used to install and run integrated Windows servers. See the topic on Predefined disk drives for integrated Windows servers.

For information about creating drives, see Create an integrated server disk drive