White Paper VERITAS Storage Foundation TM 4.1 for Windows How VERITAS Storage Foundation TM for Windows Compliments Microsoft Windows Server 2003 9/14/2004 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 Dynamic MultiPathing...6 Additional Enhancements Over Microsoft Windows Server 2003...7 Storage Management...7 Performance...7 Availability...7 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: VSFW Provider Basic Disk Provider Dynamic Disk Provider Disk Array API Microsoft VERITAS Array Vendor 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. It 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 cannot be utilized off-host. 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. VxSnap supports copy backups in the version 4.1 release of VERITAS Storage Foundation for Windows, and will support both backup types with the release of version 4.2. The Microsoft utility, ESEUTIL, will be 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. 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
MPIO Windows Server 2003 includes as a multipathing framework MPIO (Multipath I/O). 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. Dynamic MultiPathing 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 in Windows Server 2003. Figure 3 shows the MPIO stack and how DMP coexists with it. Figure 3. VERITAS DMP and MPIO co-existence Server VERITAS SFW Array Vendor Application DMP Driver MPIO Provided by: Microsoft Providers DMP Array Support Library MPIO Driver DSM ISV/IHV s VERITAS Arrays Arrays With the release of VERITAS Storage Foundation for Windows version 4.2, DMP will fully integrate with MPIO, initially for a select list of arrays, giving users the choice between VERITAS Array Support Libraries (ASLs) for traditional DMP, and VERITAS developed Device Specific Modules (DSMs) for MPIO. 6
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) 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. 7
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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