1. Hosted by NAS and Gateways Considerations for File Storage Randy Kerns Copyright © 2003 - All Rights Reserved Evaluator Group, Inc. 7720 E. Belleview Avenue Suite 210 Greenwood Village, CO 80111 (303) 221-7867 Fax: (303) 221-1615 www.evaluatorgroup.com

2. Hosted by Agenda Structure of I/O File Storage Applications – file vs. block NAS storage Structure NAS Gateways Considerations Evaluation NAS Management

3. Hosted by Structure of I/O All Open Systems use a similar I/O method minor variations some terminology differences includes all flavors of Unix includes NT/2000/XP/2003 Server Structure is for a “Layered I/O” elements in each layer has different capability layers may come from different vendors system may contain different elements at each layer depending on device or usage

4. Hosted by Layered I/O Structure

5. Hosted by File Storage File System file and directory structure on logical disk (typically single) contains metadata to describe information (size, location, dates, etc.) on the disk. Ex: superblock, inode different types of file systems with different methods of access file system handled by software in program stack of operating system multiple file systems may be present at one time “mounted” file systems or “shares” are remote file systems dev binetcusr / aps test passwd hosts Mounted file system

6. Hosted by File Systems VFSVirtual File System FFSFast File System UFSUNIX File System – used interchangeably with FFS AFSAndrew File System – also Distributed File System NFSNetwork File System – developed by Sun RFSRemote File System – developed by AT&T S5FSOriginal System V file system VxFSVeritas Journaling File System JFSJournaled File System – AIX CFSCluster file system – Tru64 EXT2/EXT32nd/3rd Extended File System – Linux systems GFSGlobal File System – Linux ReiserFSJournaling file system – Linux XFSExtended File System – SGI and others CXFSClustered Extended File System – SGI QFS64-bit very large file system – Sun Solaris HFSHierarchical File System – S/390 UNIX NTFSWindows NT/2000/2003 FATxxWindows – several versions

7. Hosted by Applications May be written to do file I/O or block I/O File I/O  Uses the file system driver  Caching done by system  Typically system utilities for management  I/O done to FILE HANDLE: Offset Block I/O  Used to bypass file system – performance reasons and overhead in capacity  Buffering/caching done by application (ie database)  Called RAW I/O  I/O typically done to blocks – linear address space  Special utilities for management

8. Hosted by Network Attached Storage

9. Hosted by NAS I/O Structure

10. Hosted by NAS Gateways The controller function of NAS with the storage decoupled Connected to a SAN – fibre channel typically May be separate product or a version of a standard NAS product can utilize SAN capabilities does introduce a different management scheme – adds the SAN storage management as well as the NAS administration

11. Hosted by NAS Gateways Typical usage profile Enterprise data center environments with existing SAN  Requirement for file storage  Consolidation of existing, independent NAS devices  Centralized administration and purchasing  Storage system partitioned for NAS filesystems (LUNs) Administration cost  Target is to reduce overall storage administration costs

12. Hosted by NAS Considerations FIRST: What are your requirements? Part of overall storage strategy  Future needs  Timeframe for deployment  Cost structures Understand needs for users, applications, business  Does application require file or block access? What environment will it used in? Enterprise data center Small to Mid-Size Business (SMB) Departmental Workgroup

13. Hosted by NAS Considerations Who will administer Dictates tools and capabilities Organizational tension Usage considerations Protocols – CIFS, NFS, HTTP, FTP, NCP Data sharing – locking requirements Connectivity – number and type of connections Security – IP/Ethernet usage, data at rest Performance  Types of data - bandwidth or response time sensitive OLTP Large Block – video, etc.  Responsiveness – guarantees, application requirements

14. Hosted by NAS Considerations Advanced services Part of consideration Requirements dictate which are of concern  Remote copy for disaster tolerance: Technology used, distance, cost, currency of data, recovery process, time to recovery  Point-in-Time copy functions: Local and remote, capacity consumed, ability to restore versions, make available read/write  Backup: LAN-free, use of SAN devices, NDMP support, favorite backup software usage  Management: incorporation into overall storage management strategy, aggregation

15. Hosted by NAS Considerations Capacity required Today and tomorrow Scaling issues  Additional NAS devices vs. additional disks  Performance scaling  Management Is a NAS Gateway the best option ? Usually environment specific  Enterprise data center with existing SAN  Storage professionals managing storage

16. Hosted by NAS Evaluation Develop a set of criteria Put in elements that are part of your requirements Give little weight to extraneous items (So What?) Evaluator Group workbook As example EG_NAS_Workbook.pdf

17. Hosted by Evolution NAS devices each individually managed  Installed and administered as unique devices Management does not scale  Additive costs for additional NAS devices Few sophisticated tools  Expectation for capacity planning, performance monitoring and reporting, and SLA adherence didn’t exist Changes are underway for NAS management NAS Management

18. Hosted by Aggregation Management software to manage multiple NAS devices Two methods  Individual devices with information accumulated Statistics, capacity information Controls, status  Multiple devices managed as single entity Dynamic allocation of capacity – adding of capacity (units) Data protection dynamically spread among devices Performance tuning by distributing data NAS Management

19. Hosted by NAS Aggregation Example Software to collect information about NAS appliances  Same vendor Unified view to monitor and control  Status and events  Capacity  Appliances, OS versions  Volumes  Disk devices Addresses admin costs in homogeneous environment Servers NAS Management

20. Hosted by NAS Aggregation Example Data accessed as if single NAS appliance – NAS array For increased capacity, add appliances Data is redistributed across appliances Clients see additional capacity with no required changes Management as a single entity Servers NAS Appliances NAS Management

21. Hosted by Summary NAS Management is maturing Economics of management / administration cost is now becoming important  Necessary with expanded use of NAS  Capacity growth accentuate the problem Need to integrate with SRM tools  Must include NAS devices from different vendors  Still a long way to go to have enterprise tools NAS Management

22. Hosted by NAS Summary Choice of NAS is an easy answer in some environments Traditional NAS usage in departmental and workgroups More difficult in enterprise data center environments  Where the requirements are understood and the attributes of NAS answer them  Where the overall storage strategy can incorporate NAS into existing environment Includes management tools Infrastructure Costs – separate IP network, NIC changes

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