Consolidating Microsoft SQL Server with HP PolyServe: The User View

Copyright © 2008 Illuminata, Inc.
TM
Consolidating Microsoft SQL Server
with HP PolyServe: The User View
Microsoft SQL Sever has enjoyed phenomenal success as a database server. ItsProduct Insight relatively low cost, steadily increasing functionality,1 and ease of deployment haveall combined to accelerate its growth. However, that same growth has led to aphenomenon that IT administrators commonly call SQL Server "sprawl"-therampant, often uncontrolled, proliferation of SQL Server databases, whether underthe purview of centralized IT administration, or tucked away under desks or inJohn Webster closets where departmental users have placed them independently of their ITGordon Haff departments.28 March 2008 This sprawl is costly because it can result in inefficient use of hardware, software,and administrative resources. Certainly, there are hardware and maintenance coststhat are magnified by this kind of inefficiency, but as we are all becoming aware,poor utilization can also rapidly increase energy consumption. And, not least,server sprawl can also rob SQL Server application users of resource availability andbusiness productivity.
HP's PolyServe Software for Microsoft SQL Server is a clustered file systemconfiguration that aims to combat SQL Server sprawl, consolidate SQL Serverenvironments, and improve application user resource availability and responsetime. According to users we recently interviewed, it successfully accomplishes
these goals, and has advantages over better-known server virtualizationapproaches. In this paper, we discuss HP PolyServe's inner workings, some of therelevant user experiences gleaned from our discussions, and how HP PolyServecompares to alternative approaches.
1 See our Microsoft SQL Server 2008.
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Clustering the File System Early CFSs mostly saw duty as failovermechanisms for Unix servers. If one server failed,Speaking generically, HP PolyServe is a clustered another could quickly take over because it hadfile system (CFS). A CFS enables sharing of direct access to all of the failed server's storage.volumes, file systems, and even individual files CFSs also gained considerable popularity in highamong applications on multiple servers as though performance computing (HPC) where a largethey were running on a single system. number of nodes often access a large quantity ofA typical single-host file system coordinates access common data. (Furthermore, HP data tends to beto data among multiple applications running "read-mostly"-that is, read more often than it'sconcurrently, and maintains "metadata" to keep written-which makes coordinating access easier.)track of where directories and files are physically Although it, too, made inroads into smaller-scalelocated; their ownership and access rights; when HPC clusters, PolyServe actually started out inthey were created, modified, and accessed; and 1999 with a focus on commercial applications. Itsother housekeeping information. Most file systems initial product, UnderStudy, was a classic HA-store their metadata on the same physical disks that clustering product for Linux, providing applicationcontain the files, using a formally-defined "on-disk and hardware monitoring and failover for twofile structure." A cluster file system extends that servers. Over time, PolyServe went on to establishsame functionality across multiple servers, while itself in a diverse set of applications including SQLkeeping application programming interfaces (APIs) Server, BizTalk, SAP, Windows Media Server,largely unchanged. The best-performers allow Citrix, SharePoint, Dynamics, Tibco, and others. Indirect I/O access to files on shared disks by each February of 2007, HP acquired PolyServe.participating server. To accomplish this, a server'sCFS manipulates on-disk file structures the same HP PolyServe Basicsway, but coordinates its activities with other clusternodes-typically through the use of some form of In the universe that includes all possible virtualized"lock manager." computing solutions, HP PolyServe lives betweenthe operating system and the storage subsystem. ItIn the case of HP PolyServe, a Distributed Lock is neither server virtualization (in the sense ofManager (DLM) allows concurrent read/write virtual machines) nor storage virtualization (in theaccess to the underlying data, and can even provide sen... [download for more]