This chapter introduces the management aspects of a file system, and discusses organizing one. The objectives important to this chapter are found on page 6-1:
Concepts:Define NSS and Its ComponentsNovell Storage Services (NSS) is discussed next. This is an enhanced, improved file system, compared to previous versions of NetWare. It is optional: you don't have to install or use it. If you do install it, it does not have to replace the traditional NetWare File System: NSS can coexist with NFS. The NSS service first scans hard drives for unused space. Whatever space is found is marked off, labeled as available to NSS, and recorded in a pool called the NSS object bank. This action is registering the space. Each of several hard drives may have free space available. The space that is marked, labeled, and recorded from each hard drive can be called a storage deposit. When NSS starts to used some of this space the storage deposit becomes a managed object. NSS can register space in NetWare partitions and in IBM-formatted (DOS) partitions. However, note that this action is essentially creating an NSS partition on the hard drive, and that there is a limit of four partitions within any IBM-formatted partition. If an IBM/DOS partition already has four partitions in it, you cannot make an NSS partition in it. This is why you do not want to create partitions within your DOS partition on the server. When NSS takes free space from a NetWare partition, NFS sees the new NSS partition as a file. NSS can mount a CD as a read-only volume. This has the advantage of making it available to users on your system. To make it possible to do so, load CDROM.NLM on your server. NSS takes its registered partitions and combines them into logical storage groups. Storage groups are combined into logical NSS volumes. The text cautions you not to combine space from inside NetWare volumes and space from outside NetWare volumes into one NSS volume. NSS volumes may be physically located on several servers, and on several
hard drives. They act as though they are on one server. Storage groups
may be combined. More storage groups may be added to NSS volumes
after the volumes are created. Describe the NSS ArchitectureThe NSS system is composed of five layers, each of which has components:
The Media Access Layer is most closely associated with hardware (storage devices). Providers and Consumers operate on this layer:
The Loadable Storage Subsystem (LSS) reads the information about available space registered by MAL. Two features of LSS are listed:
The Object Engine (OE) Layer is the location of the object bank. It uses balanced trees (B-trees) for storage, which are more efficient than standard directories. This layer is responsible for the fact that NSS can have larger and more numerous volumes and files than NFS. The Semantic Agent (SA) layer contains loadable software modules for NetWare, the Internet, and other clients that define how specific clients communicate with stored NSS objects. Think of it as a driver or interpreter section for NSS. The Common Layer Interface (CLI) contains a set of APIs that define how SAs access the object engine for the following NSS services:
List the Advantages and Disadvantages of Using NSSAdvantages:
Now the bad news. Disadvantages:
Neither good nor bad: NSS uses new utilities, REBUILD and VERIFY, instead of VREPAIR. Implement NSSNSS can be installed when you create a server, or it can be done later. Some cautions are given:
Minimum requirements for loading NSS:
The NLM that provides NSS services is NSS.NLM. It can be configured with NWCONFIG or with its own administration menus. NSS has three menus: Configure, View, and Utilities. To access them enter the following command at the server console: NSS /MENU To use NSS on an existing system, you can convert existing NetWare volumes to NS volumes, you can create NSS volumes in space not being used by existing volumes, you can repartition your hard drive, or you can install a new hard drive. To create an NSS volume, you first scan for free space, assign the free space to NSS, then create a storage group and/or volume out of that space. Manage Storage Groups and NSS Volumes
NSS storage groups and volumes can be viewed with NWCONFIG or with NSS Administration Menus. The same two utilities may be used to increase the size of (add storage groups to) an NSS volume. NFS volumes are repaired with a console utility called VREPAIR. This is not used with NSS volumes. To repair NSS volumes, use the REBUILD utility, available from the server console, and from the NSS Menus. (Note: REBUILD does not work with NFS volumes. Fair is fair...) From the console you can issue the command with a comma delimited list of volumes to repair. NetWare can only rebuild 5 volumes at a time. The command would look like this: NSS /REBUILD=NSS volume_name, NSS volume_name Volumes should be verified after rebuilding, and must be mounted before they can be used. If you use NWCONFIG to create NSS volumes, they are automatically added to NDS. If you create them in the NSS Menus, you will need to manually add them to NDS through NWCONFIG or NetWare Administrator. This sounds like an argument for using NWCONFIG. NSS volumes can be released/destroyed through NWCONFIG or the NSS Menus. Doing so will release all the storage groups in the volume, destroy the data in them, and make the space available to the NFS system. |