White Paper VERITAS Storage Foundation TM 4.2 for Windows How VERITAS Storage Foundation TM for Windows Compliments Microsoft Windows Server 2003 12/3/2004 1
Introduction...3 Storage Technologies In Windows Server 2003...3 VERITAS Storage Foundation for Windows...3 VDS...3 ASR...4 VSS...4 VERITAS FlashSnap Option...4 VERITAS Volume Snapshot Service Dynamic Provider Advantages...4 Shadow Copy Transport Off Host Capabilities...5 VxSnap...5 Microsoft Exchange Server 2003...5 MPIO...6 VERITAS Dynamic MultiPathing/MPIO Support...6 Additional Enhancements Over Microsoft Windows Server 2003...7 Storage Management...7 Performance...7 Availability...8 Summary...8 2
INTRODUCTION Microsoft introduced several new storage management features in Windows Server 2003. This paper will outline how VERITAS Storage Foundation TM for Windows (VSFW) integrates/co-exists with, and compliments these new features, and extends the capabilities of Windows with several features of its own. STORAGE TECHNOLOGIES IN WINDOWS SERVER 2003 Virtual Disk Service (VDS) - VDS enables the management of multi-vendor storage devices and is vendorneutral and technology-neutral. VDS includes two command line utilities; DISKPART for software RAID (the CLI equivalent of Windows Disk Management), and DISKRAID for hardware RAID. Automated System Recovery (ASR) - Automated System Recovery (ASR) enables bare metal restore and consistent data recovery of servers, including "system state" and hardware configuration information. Volume Shadow Copy Service (VSS) - The Volume Shadow Copy service provides an infrastructure for creating point-in-time copies (snapshots) of volumes, and includes an in-the-box VSS provider that enables the creation of shadow copies via copy-on-write technology. Microsoft guarantees the integrity of these VSS snapshots. Multipath I/O (MPIO) - Windows Server 2003 includes the framework for multipathing for creating a highly available environment in which multiple paths are available from the host to the external storage device. Multipath I/O (MPIO) is not a feature of the operating system, but Microsoft provides the MPIO Driver Development Kit (DDK), which allows storage vendors to create interoperable multipathing solutions. Up to 32 paths are supported. Load balancing is an additional benefit that improves performance. VERITAS STORAGE FOUNDATION FOR WINDOWS VERITAS Storage Foundation for Windows (VSFW) introduces features that integrate/interoperate with the new features in Windows Server 2003. Additionally, Storage Foundation extends the capabilities of Windows by providing features and functionality above and beyond those included in the OS that increase performance and availability that this paper will outline. First, let s see how VERITAS Storage Foundation compliments Windows new storage management features. VDS VERITAS Storage Foundation for Windows includes a VDS Provider, which allows VDS aware applications to manage its volumes. VERITAS applications will leverage VDS as the interface to talk to VERITAS Storage Foundation for Windows, thereby fully leveraging the technology framework that Microsoft is providing. Figure 1 shows how the Storage Foundation provider fits into the VDS stack and how applications access it via VDS. Figure 1. VERITAS VDS Provider VERITAS Applications Server Disk Admin. DISKPART CLI DISKRAID CLI Virtual Disk Service Provided by: Microsoft VERITAS Array Vendor VSFW Provider Basic Disk Provider Dynamic Disk Provider Disk Array API 3
ASR VERITAS Storage Foundation for Windows integrates with Microsoft s Automated System Recovery (ASR) so that, during a disaster recovery, ASR is intelligent with respect to VERITAS Storage Foundation for Windows volumes, which will be detected and recreated, including VERITAS Storage Foundation for Windows binaries, dynamic disk groups and private region information. VSS The FlashSnap TM Option for VERITAS Storage Foundation for Windows includes a VSS provider, VERITAS Volume Snapshot Service Dynamic Provider, and a VSS requestor, VxSnap. Figure 2.shows an overview of VSS components and how they communicate through VSS. Figure 2. VSS Components VSS writers Microsoft Exchange Server 2003 Microsoft SQL Server 2000 Active Directory VSS VSS requestors VSFW VxSnap VERITAS Backup Exec XXXXXXXX VERITAS NetBackup DHCP Windows Server 2003 COW provider Hardware Array VSS Provider VSFW VSS Provider VERITAS FlashSnap Option VERITAS focuses on creating software solutions that support any hardware on any OS. With the FlashSnap Option, VERITAS Storage Foundation for Windows (VSFW) offers a solution that leverages the VSS technology in Windows Server 2003 while offering similar functionality on Windows 2000 without VSS. On Windows Server 2003, VERITAS Storage Foundation for Windows installs a VSS snapshot provider and a VSS requestor, which provide a way to initiate and create VSS snapshots. The FlashSnap VSS provider is a software provider that creates split-mirror snapshots which are full copies of the original volumes. As full split-mirror snapshots, they require an amount of disk space equal to the size of the original volume. Unlike hardware providers, which are proprietary, the FlashSnap provider is heterogeneous i.e. all storage is seen as virtual and treated as a single pool. FlashSnap is also heterogeneous with respect to the OS. The copy-on-write (COW) provider included with Windows Server 2003 does not support Windows 2000. The VERITAS FlashSnap Option includes support for both Windows 2000 Server and Windows Server 2003. With Windows Server 2003, it utilizes the VSS framework and can therefore take advantage of the VSS guarantee of consistent snapshots. With Windows 2000, snapshots can be taken the traditional way (I/O is stopped and the file system cache flushed). The main disadvantage of this provider it that its snapshots require more disk space than COW snapshots. Following is a list of the VERITAS FlashSnap VSS provider advantages: VERITAS Volume Snapshot Service Dynamic Provider Advantages Heterogeneous Solution 4
o Windows 2000 and Windows Server 2003 will be supported, allowing for mixed Windows environments o The VERITAS FlashSnap Option is also supported on Linux, Solaris, HP-UX and AIX Integrated into Windows Server 2003 as a VSS Provider Independent Snapshot Volume o Loss of Original Volume does not affect the snapshot o Resynchronization from the snapshot volume can be done if the original volume is corrupted o Faster Performance On-host than COW Provider o Can be Moved Off-host for Processing Off-Host Capabilities o No Performance Load on Application Server o Backup Server can backup at FC Speeds (Local Volume) o No LAN Performance Impact (No Backup Agents Needed) Snapshot volume is read/writeable o Requirement for some data mining/decision planning applications Tight Integration with other VERITAS Solutions: Backup Exec, NetBackup and Volume Replicator Support for heterogeneous storage from DAS to SAN based arrays Shadow Copy Transport Off Host Capabilities Split-mirror snapshots allow for the transport of data on a SAN, which facilitates off-host processing operations such as backups, data mining, data analysis and testing. Because they re off-host, snapshot operations result in no load on the original host. Backups are faster as they re taking place at Fiber Channel speeds, with the data residing locally to the backup server rather than having to be pulled across the LAN. This results in zero performance impact on the LAN during backup. The split-mirror snapshot is readable and writeable, allowing for off-host processing without impact to the original data. VxSnap As previously stated, VERITAS Storage Foundation for Windows includes its own requestor, which initiates the snapshot process via the Storage Foundation VSS provider, to create full split-mirror snapshots with all of their advantages. Another advantage of VERITAS Storage Foundation for Windows having its own requester is that it can be used to create snapshot images which can be used for quick recovery. On their own, current backup applications such as Backup Exec (BE) and NetBackup can initiate the creation of VSS snapshots, but these snapshots are non-persistent and, prior to the release of Backup Exec version 10, cannot be utilized off-host. Backup Exec 10.0 will support off-host backups via the VERITAS FlashSnap VSS provider. Through VxSnap, these backup applications can utilize the VERITAS VSS provider to create persistent split-mirror snapshots for backup (this requires that a snapshot relationship already exist), and at the end of the operation, the snapshot can be quickly resynchronized with the original volume, awaiting the next backup. VxSnap can also create persistent split-mirror snapshot images of Microsoft Exchange Server 2003 for point-in-time and roll forward recoveries. Snapshots produced in this way will be guaranteed by VSS for consistency. Microsoft Exchange Server 2003 In addition to the many ways in which VERITAS Storage Foundation for Windows compliments Windows Server 2003, it also focuses on application specific solutions. Microsoft Exchange Server 2003 is a VSS aware application with its own VSS writer that contains information necessary to backup and restore Exchange via VSS snapshots. The Exchange writer supports both copy backups, where the transaction logs are not truncated, and full backups where log truncation occurs. With the release of VERITAS Storage Foundation 4.2 for Windows, VxSnap supports both copy and full VSS backups of Microsoft Exchange Server 2003. The Microsoft utility, ESEUTIL, is integrated as part of the full backup operation to check the consistency of the snapshot. If this check fails, a notification will be sent to the user and the logs will not be truncated. There is also an option to run ESEUTIL as part of a copy backup. VxSnap allows for point-in-time (PIT) and point-of-failure (POF) restores of Exchange. With POF recoveries, the transaction logs are rolled forward to the point of failure. VSS handles deletion of the checkpoint file as part of the restore process. VSS functionality for Exchange will also be integrated in to the VERIAS Enterprise Administrator (VEA) in a future release. 5
In addition to Quick Recovery of Exchange, VSFW and FlashSnap also support Snapshot-Assisted Backups the process of backing up a snapshot of Exchange, either on-host or off-host via traditional backup applications. Onhost backups remove the I/O load from production volumes, while off-host backups completely eliminate the I/O load on the production server. Microsoft SQL Server 2000 The FlashSnap Option also includes support for Microsoft SQL Server 2000 through the VxSnapSQL utility, which leverages SQL s Virtual Device Interface (VDI) to allow for the creation of snapshot backup sets of SQL databases and logs. VDI ensures the integrity of the snapshots. Quick recovery of SQL can be accomplished through a) recovery with log backups applied and the database brought online, returning the database to the point of the last log backup specified, b) recovery without log backups and the database brought online, which returns the database to the point at which the snapshot backup set was created, and c) recovery with the database left in a state where the user can replay log backups to any chosen point in time via the SQL Server Enterprise Manager. For more information on FlashSnap and SQL, please see the VERITAS Storage Foundation 4.2 for Windows documentation. MPIO Windows Server 2003 includes MPIO (Multipath I/O) as a multipathing framework. On its own, MPIO does not provide multipathing. Microsoft provides an API interface to Windows Server 2003 and a MPIO Driver Development Kit (DDK) which allows storage vendors to create interoperable multipathing solutions, and a selfcertification kit. Array manufacturers or third party software vendors have to create and support MPIO Device Specific Modules (DSM) for each array to be able to configure multipathing. VERITAS Dynamic MultiPathing/MPIO Support Dynamic MultiPathing (DMP), available as an option to VERITAS Storage Foundation for Windows, is VERITAS multipathing solution for Windows. DMP provides an enterprise solution that is supported on both Windows 2000 and Windows Server 2003. It is also supported on the other major OS platforms Linux, Solaris, HP-UX and AIX. DMP currently supports an extensive list of hardware arrays via Array Support Libraries written for each array type/family in Windows 2000 and extends this list in Windows Server 2003 for arrays supported by Windows Server 2003. With the release of VERITAS Storage Foundation 4.2 for Windows, DMP will fully integrate with MPIO, giving users the choice between VERITAS Array Support Libraries (ASLs) for legacy DMP, and VERITAS developed Device Specific Modules (DSMs) for MPIO. In it s this release, DMP will support EMC Symmetrix and DMX arrays via a device specific module written for those arrays. DMP supports three modes of operation through its ASLs. An Active/Passive configuration, offers a conventional path failover setup, with one path being used for all I/O, and inactive secondary path(s) held in reserve, ready to take over, should the primary path fail. In Active/Active mode all paths are available, and DMP software balances I/O traffic evenly between the resources using a Round-Robin algorithm. Active/Passive Concurrent is similar to Active/Active in that all paths to storage are used. However, unlike the Round-Robin approach of Active/Active, Active/Passive Concurrent mode binds each device to a specific path, with I/O being routed based on destination. With the introduction of MPIO support in VSFW 4.2 comes a new load balancing algorithm Dynamic Least Queue Depth: With Dynamic Least Queue Depth, the path that will be used to transfer I/O will be the path with the least I/O requests. Figure 3. VERITAS DMP and MPIO Server VERITAS SFW Array Vendor Application Provided by: Microsoft Providers DMP Driver DMP Array Support Library MPIO MPIO Driver DSM ISV/IHV s VERITAS Arrays Arrays 6
iscsi With the emergence of iscsi as a serious protocol for attaching to storage, Microsoft has introduced support for it through their iscsi initiator, which is a software initiator. In addition to the software initiator, iscsi HBAs, also known as TOEs (TCP/IP Offload Engine), allow you to connect to storage via the iscsi protocol. One of the advantages of using a hardware initiator versus a software initiator is that the disks are available at boot time. The software initiator s main advantage is price; it is available with the OS. VERITAS Storage Foundation 4.2 for Windows supports iscsi via the Microsoft iscsi initiator and a hardware initiator, the Qlogic QLA4010 iscsi HBA. DMP is supported with the QLA4010 iscsi HBA, but not with the Microsoft iscsi initiator. Due to the fact that disks aren t available at boot time when using the Microsoft iscsi initiator, VSFW 4.2 includes the Dynamic Disk Group Delayed Import Service (VxDGDI), which can be enabled to delay the import of specified dynamic disk groups until after the iscsi initiator initializes and disks are available. The dynamic disk groups to be delayed, the ones that include iscsi disks, are listed in the registry under the subkey HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\vxio\LateStart. Service dependencies have to be set via the registry so that applications that depend on iscsi disks have a dependency on the VxDGDI service, which in turn depends on the MS iscsi initiator. Due to the fact that not all users will use the isoftware initiator, the VxDGDI service is set to manual start by default, and would need to be set to Automatic when the service is enabled. ADDITIONAL ENHANCEMENTS OVER MICROSOFT WINDOWS SERVER 2003 In addition to the Windows Server 2003 features discussed above, VERITAS Storage Foundation for Windows offers several new features and options that extend the capabilities of Windows. The following features, which are not available in Windows Server 2003, are available in VERITAS Storage Foundation for Windows: STORAGE MANAGEMENT VERITAS Storage Foundation for Windows provides capabilities for centralized Storage Management & Reporting VERITAS Enterprise Administrator Configure and manage remote storage while the system remains online. Configure and manage different volume layouts, including mirrored striped volumes and up to 32-way mirrors. Drag & Drop GUI Easily migrate data to new storage from the GUI. AutoGrow Automatic, policy based volume growth. Dynamic Relayout Dynamically relayout volume configurations while keeping volumes online. Multiple Disk Groups Storage Event Log Notification Proactive Storage Resource Monitoring PERFORMANCE VERITAS Storage Foundation for Windows improves system and disk performance with: Hot spot detection via performance monitoring Subdisk Move, Split and Join - Performance tuning via moving subdisks from areas of high I/O activity (hot spots) to disks with lower usage. Subdisks can also be split to allow for evenly spreading the load across multiple disks. VxCache Volume based caching to facilitate improved performance for read intensive applications. On VxCache enabled volumes, data is stored in and read from memory, as opposed to being read from slower disks. Mirrored volume read policies (Round Robin or Preferred) 7
Capacity monitoring Event monitoring Real Time Statistics Collection and Display Historical Statistics Collection and Graphing AVAILABILITY Dirty Region Logging (DRL) A log based recovery method to quickly resynchronize mirrored volumes after a system crash. RAID-5 Logging RAID-5 volumes can be quickly reactivated after a system crash. Disk Replacement A failed dynamic disk can be replaced by an empty basic disk. Volume configurations will be recreated. Disk Evacuation The entire contents of a healthy disk can be moved to the free space on one or more dynamic disks. Hot Relocation Subdisks of redundant volumes are moved from failed disks to hot spare disks. They can be moved back to their original location after the the failed disk has been repaired or replaced with the Undo Hot Relocation command. AutoGrow Policy based automatic volume growth Cluster Support, including Campus Clusters, for dynamic disks/volumes (MSCS Quorum resource can be made fault tolerant) VERITAS Storage Foundation for Windows will also integrate seamlessly with VERITAS Volume Replicator and the Global Cluster Option in its High Availability and Disaster Recovery versions for a very powerful wide area disaster recovery solution. SUMMARY Microsoft introduces new storage management technologies in Windows Server 2003. VERITAS Storage Foundation for Windows offers technologies that integrate or transparently co-exist with those in Windows Server 2003 along with a variety of other features which extend the capabilities of Windows Server 2003. The VERITAS Storage Foundation for Windows snapshot provider enhances VSS by allowing the creation of VSS enabled snapshots that are true copies of the original data and are therefore not dependent on the original volume, thereby providing redundancy, and which can be split off from the original volume and utilized for various off-host operations. A snapshot requester allows users to request VSS enabled snapshots for applications such as Microsoft Exchange 2003. With VSS snapshots, the integrity of those snapshots is assured. DMP provides the ability to enable path redundancy for a wide variety of storage arrays via array specific libraries (ASL). With the release of VERITAS Storage Foundation for Windows 4.2, VERITAS will integrate DMP with MPIO by providing Device Specific Modules for a specific list of storage arrays in addition to the array specific libraries currently supported. While MPIO is only supported in Windows Server 2003, with its ASLs DMP supports both Windows 2000 and Windows Server 2003. With integrated support for ASR users are guaranteed complete recovery of a system, including volumes and dynamic disk group configurations that were created with VERITAS Storage Foundation for Windows, and the VDS provider allows you to fully leverage the Virtual Disk Service included in Windows Serer 2003. 8
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