MSCS 2003 Cluster Virtual Server Components

This post provides my interpretation of a simple MSCS 2003 virtual server with a file share, including how the cluster interacts with the OS and network services to provide access to the share. This follows on from the last post on low-level detail of file access in an attempt to provide a clearer picture of these often taken-for-granted components.

Note that this is only my opinion, based on less-than complete knowledge and more than likely contains semantic errors if nothing else.

File & Print Cluster Native x64 (EM64T/AMD64)

1. Cluster Service. Includes Checkpoint Manager, Database Manager, Event Log Replication Manager, Failover Manager, Global Update Manager, Log Manager, Membership Manager, Node Manager.
1. Operating System Interaction with the LanManServer Service which advertised shares.
2. NetBIOS registration of the virtual server name through existing network services
3. DNS registration of the virtual server name through existing network services
4. Kerberos SPNs registered against an AD computer account through Active Directory
2. Resource Monitor. Spawned child process of the cluster service, separate resource monitors can exist for resource DLLs
3. ClusRes.dll Physical Disk <-> IsAlive/LooksAlive SCSI reservation and directory access. LooksAlive issues a SCSI reservation every 3 seconds through ClusDisk.sys against all managed disks. IsAlive performs a ‘dir’ equivalent
4. ClusRes.dll Network Name <-> IsAlive/LooksAlive check on NetBT/DNS registration. LooksAlive relies on MSCS NIC failure detection. IsAlive queries local TCP/IP stack for virtual IP and the NetBT driver if NetBIOS is enabled
5. ClusRes.dll IP Address <-> IsAlive/LooksAlive check on cluster NIC. LooksAlive queries NetBT driver and every 24 hours issues a dynamic DNS host record registration. If ‘DNS is required’ resource will fail if DNS registration fails. Same test for IsAlive
6. ClusRes.dll Resource DLL File Shares <-> IsAlive/LooksAlive check on file share visibility. LooksAlive queries lanmanserver service for the share name. IsAlive does the same, and if unlimited users, the first file on the share is copied
7. 32-bit Resource Monitor WOW64, Eg. Enterprise Vault Cluster application. Third-party cluster resources, eg Enterprise Vault, which in this case notifies the local FSA placeholder service on each physical node of virtual server changes
8. ABE enabled by generic cluster resource. Access based enumeration with a generic cluster application running abecmd.exe during virtual server/share creation. Uses 32-bit cluster resource monitor with WOW64, setting SHI1005_FLAGS_ACCESS_BASED_DIRECTORY_ENUM (0x0800) flag set on the otherwise standard share.

Pretty picture view:

References

Server side processes for simple file access
http://waynes-world-it.blogspot.com/2008/11/server-side-process-for-simple-file.html

Access Based Enumeration
http://technet.microsoft.com/en-us/library/cc784710.aspx

SHARE_INFO_1005 Structure
http://msdn.microsoft.com/en-us/library/bb525404.aspx

Wayne's World of IT (WWoIT), Copyright 2008 Wayne Martin.