G.0 NSS Nomenclature

This section describes the nomenclature used for key Novell Storage Services media objects in Novell Open Enterprise Server 2. This information can help you better understand the nature of error messages you might receive when using NSS. The table identifies the media object, defines it, and indicates the version of NetWare or OES where the media object first appeared.

NOTE:All ZLSS (NSS Journaled Storage System) file blocks are 4 KB in size.

Media Object


Version Where First Used

Area Seed

To improve performance for OES 2 Linux, metadata blocks use an area seed logic to make sure that related metadata blocks are physically stored near each other. For information about configuring area size, see Section 27.3.1, Viewing the Metadata Area Size.

OES 2 Linux (not available on NetWare)

Beast B-Tree

The Balanced Tree (B-Tree) that tracks all the file’s metadata. This includes when the file was created, who created the file, the size of the file, and the location of the file’s data.

NetWare 5.0


Four blocks (one in each Superblock) that track where to start playing the journal if the server crashes. The checkpoint contains the metadata of the Journal.

NetWare 5.0

Directory B-Tree

Used to implement an NSS volume’s Directory Quota feature.

NetWare 5.0 Support Packs

Entry ID (EID)

An eDirectory entry within the FLAIM database (the underlying database for Directory Services 8.35 and later, including all eDirectory versions). EIDs are 32 bits and are unique for each server.

EIDs are used within eDirectory to reference objects on a specific server. They are unique for each object for each server, meaning that object CN=Admin.O=EMA_CORP potentially has a different EID on server FS1 than on server FS2.

This can be demonstrated with dsbrowse.nlm, a tool you can use to examine the local eDirectory database on the NetWare server. If you examine an object on one server and compare it with the same object on another server, the EID between the two instances of the object are probably dissimilar.

NetWare 6.0

Epoch File Log (EFL) B-Tree

Tracks files that change during an administrator-specified interval of time called an epoch. This feature is used by Novell Archive and Version Services.

NetWare 6.5

Globally Unique ID (GUID)

A globally unique identifier within eDirectory. The scope of this uniqueness is within one tree, although no actual checking is done to ensure this.

GUIDs are 128 bits and are unique for each object. GUIDs allow an object to be referenced no matter which server you are accessing.

NetWare 5.0


The file used to quickly make the file system consistent after a server crash. The journal is sometimes referred to as a zlog.

NetWare 5.0

Logged Pool Data Block

The block that tracks information about the pool, including the number of used blocks and salvageable blocks. Holds some of the items found in the zPoolInfo_s portion of the zInfo_s structure.

NetWare 6.0

Logged Volume Data Block

The block that tracks the number of files, used blocks, and compressed files of a volume. Holds some of the items found in the zVolumeInfo_s portion of the zInfo_s structure.

NetWare 5.0

Modified File List (MFL) B-Tree

Tracks files and folders that have the Archive attribute set by the user. The Archive flag indicates that the file or folder needs to be backed up. NSS uses this list to quickly find files that need to be backed up during scheduled backups. This Archive file-and-folder attribute is unrelated to Novell Archive and Version Services.

NetWare 6.0

Multiple Server Access Protection (MSAP)

The block used to reduce accidental use of a pool by more than one server at a time. A single copy of this block is stored in the second Superblock.

NetWare 6.0 Support Packs

Name Tree B-Tree

The B-Tree that tracks the directory structure of a volume.

NetWare 5.0

Pool Data Block

The block that tracks persistent pool configurable items. For example, a pool’s features are stored here. Holds some of the items found in zPoolInfo_s portion of the zInfo_s structure.

NetWare 6.0

Purge Log

Tracks transactions over an extended period so they can be completed after a crash. For example, the log records file deletes and truncates that need to be completed after a crash.

NetWare 5.0

Purge Tree B-Tree

Used to store information about all salvageable files. This tree is used when the file system needs to autopurge files to create free blocks.

NetWare 5.0


Used by the Media Manager to track pool snapshots. The object tracks which snapshots exist on a pool and where all blocks of a snapshot are stored. The root of this object resides in the first Superblock. All other blocks are allocated from a file on the internal volume.

NetWare 6.5


There are four Superblocks of 16 blocks each. The four Superblocks are replicas that reside in four fixed locations within the pool. The Superblock is used by the Checkpoints, Superblock Header, Snapshot, and Multiple Server Access Prevention.

NetWare 5.0

Superblock Header

Four blocks (copies of each other, one in each Superblock) used to locate all other ZLSS media objects. These are the first blocks that the file system reads when a volume is loaded. Starting with NetWare 6.0, these blocks are read when a pool is loaded.

NetWare 5.0

User B-Tree

Used to implement an NSS volume’s User Quota feature. Starting with NetWare 6.0, the B-Tree also stores Novell eDirectory information related to User Quota.

NetWare 5.0 Support Packs

Volume Data Block

The block that tracks configurable items in NSS volumes such as the volume’s attributes and the high and low watermarks for salvage. It holds some of the items found in zVolumeInfo_s portion of the zInfo_s structure.

NetWare 5.0


A numeric ID within the NSS file system, used to reference an object with the object store (also known as the beast tree). ZIDs are 64 bits and are unique for each volume.

The number of ZIDs is limited to 4 billion (4xE9) because of 32-bit limitations from the client. ZIDs are not reused, so if your processes create and delete lots of files in a volume, the numbering of ZIDs might approach this limit. and cause files not to be allowed to be created. If this occurs, you should rebuild the pool to renumber the files, referred to as reZIDing. For more information, see Section 16.3, ReZIDing Volumes in an NSS Pool.

NetWare 6.0