Cisco Wide Area File Services La centralizzazione dei File Services

Transcription

1 Cisco Wide Area File Services La centralizzazione dei File Services Vimercate, 17 Maggio 2005 Andrea Verri Consulting Systems Engineer Cisco Systems Session Number 1

2 WAFS Solution Overview 2

3 The Business Drivers Data Protection Centrally Protect Branch Office Data Branch Consolidation Consolidate File & Print Servers File Access & Sharing Near-LAN File Access Performance Enabling Branch Infrastructure Consolidation 3

4 Typical Enterprise Branch Office Regional Office IT IT Backup NAS DAS DAS Backup NAS DAS DAS Files Files IT Wide Area Network NAS SAN IT Backup NAS DAS DAS Files Files Remote Office Data Center Islands of Storage 4

5 Cisco WAFS Solution Branch Office Regional Office IT IT Backup Backup NAS DAS DAS WAFS Central Manager NAS DAS DAS Files Files Files (Web-based) Edge FE Edge FE Files IT Admin Core FE NAS SAN IT Wide Area Network Backup Files Edge FE Files Data Center Cluster NAS DAS DAS Files Remote Office Wide Area File Services 5

6 Concept: Centralized File Services Provision file services in branch via central file server Eliminate the need for branch office file servers Extend file services for desktops (.PST, My Documents) Transparency and Simplicity Black box appliance, Zero-branch management Users/apps see standard Network Drive Integrated in IT Infrastructure Central configuration and monitoring 6

7 The Challenges Challenge #1: Providing ubiquitous access to reliable information to employees regardless of location Challenge #2: Centrally manage and host web, applications, media, file servers and storage infrastructure with high performance, reliable access Challenge #3: Overcome network-induced bottlenecks to application performance Link Latency Application Protocol Chattiness Limited bandwidth and need for bandwidth control TCP Issues with High BDP Networks, Congestion Control and Packet Drops Fast, reliable access to centrally hosted Applications, Content and Storage from remote locations across the WAN 7

8 The Challenges Performance is key: near-lan response time Latency is the major problem in CIFS apps Over 1000 CIFS messages on Microsoft Word 1MB File Save 40% signaling messages Synchronous client waits for response before continuing More bandwidth does not solve the problem Enhance utilization of existing bandwidth But cannot compromise on: Correctness: compliance with protocol semantics Data assurance: No data loss or corruption Security: authentication and authorization Scalability: Support thousands remote sites Reliability & HA: Minimize service interruption at branch 8

9 CIFS The Latency Problem 9

10 WAFS Solution Only small fraction with WAN delay 10

11 Cisco File Engine Performance Word - Time to Open Word - Time to Save Native WAN Cisco FE Native LAN Native WAN Cisco FE Native LAN MB Word File (sec) Excel - Time to Open Excel - Time to Save Native WAN Cisco FE Native LAN Native WAN Cisco FE Native LAN MB Excel File (sec) Network Link T1, 80ms latency Cisco File Engine shows 4x to 9x faster performance vs. the WAN, and similar performance to the LAN for typical operations on Microsoft Windows Office applications 11

12 Cisco File Engine Fast Performance Segment data & Metadata Caching Protocol Specific Latency Reduction WAN transport-level optimizations Policy-based Preposition Complete Data Integrity Native end-to-end CIFS/NFS Support Global Locking & Coherency Validate on Open, Flush on Close Unsurpassed Reliability CoreServer Clustering Watchdog, Heartbeat, SNMP Alerts Transactional Cache for Recovery Enterprise-Class Solution Scalability, performance, availability Web Based central management Print Services, SW Distribution 12

13 Cisco WAFS Architecture Session Number 13

14 WAFS Architecture Overview Central Manager IT Admin (Web-based) XML/HTTP Windows Client Windows File Server Storage Array Unix/Linux File Server DATA CENTER Std. TCP/IP Wide Area Network LAN NAS LAN SAN CIFS NFS Unix/Linux Client BRANCH OFFICE Full CIFS implementation Proprietary WAN protocol 14

15 WAFS Deployment Concepts No Proprietary Agents on clients or servers Using standard protocols CIFS & NFS Edge File Engine appears as std. File Server on the LAN All File & Print AAA delegated to relevant Authorities NT4 Domain Controller, Microsoft Active Directory, NIS Stateless, Active-Active Clustering at the Core 15

16 WAFS is a CIFS/NFS WAN Adaptation Layer 17

17 Architecture Highlights CIFS Performance via Caching and WAN acceleration WAFS handles most (nearly 90%) CIFS ops with local response Eliminates most latency overhead Frees scarce bandwidth resources Faster than any WAN acceleration WAN Optimizations Pre-position, read-ahead, pipelining, compression End-to-end CIFS support Compliance: All Windows/CIFS semantics supportable Correctness: Coherency, Concurrency, Assurance Centralized authorization and authentication Transparent Integration with Windows Networking 18

18 Data Read-Write Caching CIFS Segment-based No need to wait for whole file to be fetched before serving Read-ahead triggered on sequential access (configurable) Random access apps never bring whole file ( explorer ) On Writes: only updated segments propagate to server Write-back (asynchronous) caching Small writes buffered in Edge FE, pipelined in transport Masking the impact of WAN latency Full BW utilization Continuously streaming data back to server 19

19 Meta-Data and Protocol Caching CIFS Safe and effective caching of file attributes During file access During browse/search, even when file data is not cached Cache redundant protocol commands Batch and issue composite commands Operation Sequence Prediction/Reduction Predict lock sequence and reduce round-trips MS RPC caching Supports CIFS over NetBIOS Legacy Support Supports redirection of Native CIFS clients 20

20 Example of Optimizations CIFS Operation MS Office mix: Frequency of operations Category WAFS QUERY_FILE_INFO 19.6% meta-data read cacheable QUERY_PATH_INFO 5.3% meta-data read cacheable FIND_FIRST2 1.1% meta-data read cacheable Check Directory 0.8% meta-data read cacheable Trans 0.2% meta-data read cacheable Find Next 0.8% meta-data read cacheable QUERY_FS_INFO 0.5% meta-data read cacheable READ 46.0% data read cacheable LOCK/UNLOCK (cacheable) 2.7% signaling cacheable NT_Create_AndX (Open) 3.0% signaling cacheable Total Cachable 80% WRITE 12.2% data write asynchrounous SET_FILE_INFO 2.2% meta-data write asynchrounous Close (non-dirty) 1.7% meta-data asynchrounous 96% of all messages handled locally Total asynchronous 16% Session Setup AndX 0.6% session not cacheable Tree Connect AndX 0.4% session not cacheable Tree Disconnect 0.4% session not cacheable Logoff AndX 0.3% session not cacheable Close (dirty) 1.1% meta-data write not cacheable Delete 0.3% meta-data write not cacheable Flush 0.1% meta-data write not cacheable LOCK/UNLOCK (not cacheable) 0.7% signaling not cacheable Total not cacheable 4% Total 100% MS RPC 3-5% signaling cacheable 21

21 Performance Summary Graph CIFS Microsoft Office Applications Performance Response Time (Sec) ActStor 1.544Mbps LAN WAN 1.544Mbps ActaStor256K WAN 256k Latency(ms) 22

22 Protocol Correctness CIFS Flush-on-close ensures all data safely in File server Supports quota restrictions and disk-full scenarios Byte-range Locks and Open share modes propagate to file server, ensuring global consistency in file access Validation model and flush-on-close ensure coherency in file access 23

23 Authentication & Authorization CIFS Transparent Authentication/Authorization Authentication done at the Core Pass-through session log-on Supports NTLM, Kerberos & Future Enhancements Authorization done at the Core Pass-through Open file operation delegated to File Server Zero User Administration No privileged user at Core FE No new users/permissions at the edge 24

24 Read-Write Caching NFS Edge FE acts as a NFSv2 Server File site limit ( <2GB) Packet size limit (8KB) Max number of shares limited by packet size Synchronized Metadata and File data Age-based Revalidation Meta-data updates both locally and remotely Unlike CIFS, Write-back caching not supported yet nfs-clients often perform their own write-back caching Cache negative responses Full NFS Coherency and Locking, within site boundaries Multi-level Coherency Symbolic links fully supported Hard-links treated as File Instances 25

25 Authentication & Authorization NFS Client is responsible of Authentication & Authorization UID/GID Mapping capabilities GID/UID of user josh in site A, to GID/UID of user josh in site B (i.e., go by the user name, not GID/UID) All users/groups in site A map to a single GID/UID in site B Accommodate NFS Server Root Squash Zero User Administration No privileged user at Core FE No new users/permissions at the edge 26

26 Design for Scalability and Reliability Core Engine: Offloaded WAFS Core Engine and File Server Most reads handled at cache Core mostly handles updated (write) segments Stateless Core Engine lends to safe Clustering Linear scale up with clustering and load balancing Edge: WCCP (Future) Support for clustering and bypass Integrated with DFS Failover 27

27 WAFS CIFS Integration Example Edge FE exports file server as std. servers on the LAN Exported File Server shares visible in Network Neighborhood Naming options: Prefix/suffix, name aliases Global Naming via Microsoft DFS WAFS 3.0 : Transparent CIFS Proxy (WCCP, Layer 4 Switching) Windows Client CIFS File Server Name: Pluto \\Pluto\Demo Core Core FE Core FE Name: Core FE Name: CFE1 Name: CFE1 Name: Core1 Core1 Edge Edge FE FE Name: Name: Br1Cache Br1Cache \\BR1-Pluto\Demo Data Center Branch1 29

28 WAN Transport Optimization Pipelining for effective bandwidth utilization Persistent Connection Prioritized Message Queue Order preserving operations per client Asynchronous (buffered) writes Overcomes delays due to clients doing small writes Buffer large enough to cover BDP size Read ahead large buffers, and rest of file Segment Level LZ Compression Multiplexing over multiple sockets Dynamic socket allocation - efficiency Accommodate High Packet Loss Accommodate TCP delays and overhead WAFS QoS: prioritize WAFS messages Flow control to avoid overflow at Core/Edge Bandwidth control to avoid link saturation (Configurable Bandwidth Throttling) 31

29 Pre-Position Scheduled distribution from center to branches Content & Destination Selection Regular-expression content selection Flexible destination selection (single, group, all) Flexible operation Time Window (e.g., 9pm 6am) Space limits Efficient Transfer Only missing blocks, changed files 32

30 Windows Print Services Works with any Printer Uses RAW mode Client does the rendering Print Services + Queue Management Web-based GUI Windows Wizards Job control and Status Monitoring Print Server Configuration: Basic network parameters (IP addr, Name, etc.) Queue Definition and ACLs Client Driver Uploads supports Click n Print Standard Windows wizards for printer settings and accessories 33

31 File Engine Management Web-based Centralized Control & Monitoring Centrally configure & monitor all gateway or groups of gateways Comprehensive statistics and reporting, SNMP Automatic central upgrade 34

32 Edge File Engine Statistics Pattern Regularity 35

33 Cisco WAFS Reliability and Availability Session Number 37

34 Core - Reliability and Availability Simple N+1 Stateless Core Clustering Stateless Core w/ simple failover with NO loss of performance Will operate when network disconnected Cluster over WAN is supported No Core FE s wish-list for Edge FE s (planned) 38

35 Edge - Reliability and Availability Edge FE Persistent, Transactional, Recoverable cache Watchdog process Clustering/Failover via DFS Journaling File System Hardware redundancy RAID support Disconnected operation Masks intermittent disconnects (90 sec retry) Clean transition to no-service on long disconnects Edge FE supports Windows Offline Folders Clients automatically reestablish connection Warm-start Capabilities Re-use existing cached data Recovery from failures Rollback uncommitted transactions Remove corrupted data Sync with Meta-data Revalidate cached resources 39

36 WAFS File Engine Scalability Edge FE Scalability Determined by user activity, avg. file size, bandwidth Criteria: set limit on max response times Knowledge workers Multiple Edge FEs per site via DFS or WCCP (Future) Core FE Scalability Determined by Edge FE load, bandwidth Edge FE per Core FE Clustering provides near linear scale up 40

37 Client and Edge FE Reliability If FE fail Client will be remapped to a new FE if DFS or WCCP -or- Client will fail to operate on the file like a local disk went down Remember the working file is in the Client Application buffer No real data loss If WAN link will fail WAFS guarantees 90 secs for flapping links For more that 90 secs like FE fail 41

38 ACNS & WAFS Solutions Web & Video Services File & Print Services ACNS Web App. Acceleration Intranet Portal Enterprise App. Acceleration Web Caching HTTP HTTPS FTP TFTP DNS Secure Content Management Business Video elearning Corp Communications POS Video Display MMS RTSP Web App Policy Enforcement Access Control Secure Internet/Intranet Proxy WAFS Branch Infrastructure Consolidation File & Print Server Consolidation Edge Data Protection File Access & Distribution CIFS/NFS 42

39 Customer Benefits Lower TCO: File & print servers and tape backup consolidated. Extend Data Center NAS/SAN infrastructure to the branch Branch Data Protection: Master copies of files stored in data center and centrally managed & protected Reduced IT administration: Centrally manage file services such as user quota, backups, access control, security policies, restores etc. Global Data Access: Centralized file storage with near-local LAN edge access performance enables distributed collaboration Cisco Global Support & Service Clear ROI 43

40 Cisco WAFS Summary Data Protection Branch Consolidation File Access & Sharing Wide Area File Services (WAFS) Enables Customers to Realize: Fast ROI through reduced OpEx and CapEx Achieve IT & Legal Compliance objectives to protect branch data Greater Productivity 44

41 2003, 2004 Cisco Systems, Inc. All rights reserved. 45