STORAGE ARCHITECTURE/ MASTER): Where IP and FC Storage Fit in Your Enterprise

Randy Kerns Senior Partner The Evaluator Group

Agenda



Storage Connection

• •

Fibre Channel IP



NAS



iSCSI



Planning



Usage

Storage connection



Fibre Channel

•

Used in Storage Area Networks (SAN)



Enterprise datacenter environments



In SMB – primarily with packaged solution “SAN in a Box”

• •

Direct connection from servers to storage systems Used in storage systems for drive connections

Fibre channel



Targeted at block-level I/O for high performance



Heterogeneous storage and server attachment



Nearly unlimited scaling of storage

•

capacity

•

performance (bandwidth)



Centralized administration



Shared resources – pooling of devices



Enterprise class capabilities – RAS, capacity planning, business continuity

Fibre channel (2)

Clients Local Area Network Servers SAN JBOD

Disk array

ATL

Storage connection



Network Attached Storage (NAS)

•

Special purpose device to provide remote file system to other servers on the network

•

Usually a kernel or thin server that supports NFS, CIFS, HTTP and FTP



some implement standard server and call it NAS



single purpose devices are called appliances

•

Utilizes IP for connection protocol and UDP or TCP

NAS



Simplicity – easy to install and administer



High Availability – many NAS devices are fault tolerant and support internal failover



Scalability – most NAS devices can scale in capacity and performance up to a point (upper limit)



Connectivity – utilizes standard network infrastructures (typically Ethernet) and supports multiple connections

NAS (2)



Access – done with NFS and CIFS



Data Sharing – a basic function of NAS for files



Cost – significant competition has driven costs down. Many offerings from wide range of vendors



Backup – beginning to see backup over SANs, but many have integrated backup devices to avoid LAN usage

NAS (3)

Workstation Workstation

Server

NAS

Storage

Disk array Host Tower box

LAN

I/O Requests for for File I/O using NFS, CIFS Server owns storage device and does block level I/O

0/0

1.

2.

Do you have NAS installed in:

30% 30%

Departments in larger companies

20% 20%

Enterprise Data Center 3.

Small to mid-size business 4.

None

1 2 3 4

Storage connection



iSCSI – Internet SCSI

• • • Use of SCSI commands over IP Target is to provide block I/O using Ethernet infrastructure No mechanism in Ethernet/IP to allow for command-response structure of SCSI  SCSI is block oriented storage interface  Both an interface and a protocol • Ethernet / IP has network characteristics  No flow control – drops packets on congestion  Packet size is limited – get smaller as contention increases  iSCSI attempts to work within these constraints

iSCSI mapping over IP

iSCSI TCP IP

Open Systems Interconnect Model Application Presentation Session Transport Network Data Link Physical

Abstraction of network for access by application. The application will do a read or write operation either to a device or a file.

Data transformation occurs to present in a uniform manner. This is implemented with the application layer.

iSCSI is established as an application session to map SCSI on top of TCP Responsible for end-to-end delivery utilizing two services: connection oriented (TCP) and connectionless (UDP).

Routing of data packets between systems with intermediate systems. Usual protocol implement for this is IP (Internet Protocol).

Data transfer across medium including error checking, forwarding and retransmission requests. Example is Ethernet.

Type of communication medium (copper, fibre, RF), signal modulation, bit encoding

iSCSI – Encapsulation

Ethernet Header IP Header TCP Header iSCSI Header Data Up to 1,450 Bytes CRC

Delivery of iSCSI Protocol Data Unit (PDU) to contain state and control information for SCSI Reliable transport software information for delivery and ordering. Internet Protocol for routing through a network Physical network interface and control for Ethernet

iSCSI – Encapsulation mapping SCSI Comand Descriptor Block and Data Header iSCSI PDU Data Header iSCSI PDU Data Header iSCSI PDU Data IP Packet IP Packet IP Packet IP Packet IP Packet No Natural Alignment for Encapsulation

iSCSI usage

IP SAN Using iSCSI Servers

Ethernet

Ethernet Switch

Network 10/100 Gig-E Sonet/SDH ATM

Storage System Remote Site

iSCSI usage (2)

iSCSI Connection for Stranded Servers Servers FC to IP Routers Fibre Channel Fabric Storage Systems Stranded Servers

0/0

If you plan on using iSCSI, will it be for:

40%

1.

An IP SAN

30% 30%

2.

Connect stranded servers 3.

Both

1 2 3

Planning



Understand requirements

• • •

Look at performance, security, cost, availability Understand administrative issues and needs Look at needs in the future



Decide which solutions fit the requirements

• •

Technology characteristics Consider the economics



Administrative costs



Expansion costs



Device / infrastructure costs

Usage



Enterprise DataCenter market

•

Majority of companies have deployed FC SANs



> 80% in some form



> Half of storage in storage network

•

Most have single switch/director vendor for specific SAN



Want to manage only one type

•

Many have only one storage vendor per SAN



Because that’s the way salesmen sold it

•

NAS Gateways are seeing deployments



Major vendors offering gateways



New challenge for storage administrators



Establishes presence for NAS in Enterprise Datacenters

•

Customer focus is now on storage management

Usage (2)



Small to mid-size business

•

FC SAN is usually packaged “SAN in a box” solution



No storage professionals to implement or manage a SAN



Percentage-wise, a small amount of deployment

•

IP SANs are early in deployment



Typically in very cost-sensitive environments



Still storage administration to do

•

NAS is very successful in SMB market



Also departmental and workgroup



Fits well with requirements

•

Market open for many types of solutions



Large and growing market with varying requirements

Summary



Choose wisely

• • • •

Performance requirement – FC Minimal administration and file I/O – choose NAS Connect stranded server cheaply – iSCSI Block I/O with minimal cost and not a high performance requirement – iSCSI or packaged FC solution